Add link to issue on non-testability of the Dynamic Code Brand Checks proposal.

Following up on `@ljharb`'s suggestion #535 (comment)

Author: ioannad

README.md

@@ -27,14 +27,13 @@ Stage 2 indicates that the committee expects these features to be developed and
 | [Decorator Metadata][decorator-metadata]                                       | Kristen Hewell Garrett                                                  | Kristen Hewell Garrett                                                  | <sub>[decorator-metadata][decorator-metadata-tests]</sub>           | <sub>[May&nbsp;2023][decorator-metadata-notes]</sub>       |
 | [Source Phase Imports][source-phase-imports]                                   | Luca Casonato                                                           | Guy Bedford<br />Luca Casonato                                          | <sub>[source-phase-imports][source-phase-imports-tests]</sub>       | <sub>[July&nbsp;2023][source-phase-imports-notes]</sub>    |
 | [Time Zone Canonicalization][time-zone-canon]                                  | Justin Grant                                                            | Justin Grant<br />Richard Gibson                                        | <sub>[Temporal.TimeZone][time-zone-canon-tests]                     | <sub>[July&nbsp;2023][time-zone-canon-notes]</sub>         |
-| [Dynamic Code Brand Checks][dynamic-code-brand-checks]                         | Nicolò Ribaudo                                                          | Krzysztof Kotowicz<br />Mike Samuel<br />Nicolò Ribaudo                 | :question:                                                          | <sub>April&nbsp;2024</sub>                                 |
+| [Dynamic Code Brand Checks][dynamic-code-brand-checks]                         | Nicolo Ribaudo                                                          | Krzysztof Kotowicz<br />Mike Samuel<br />Nicolo Ribaudo                 | <sub>[No test262 tests][dynamic-code-brand-checks-no-tests]         | <sub>April&nbsp;2024</sub>                                 |
 | [`Atomics.pause`][atomics-pause]                                               | Shu-yu Guo                                                              | Shu-yu Guo                                                              | <sub>[Atomics.pause][atomics-pause-tests]</sub>                     | <sub>[October&nbsp;2024][atomics-pause-notes]</sub>        |
 | [Deferring Module Evaluation][lazy-import]                                     | Yulia Startsev<br />Guy Bedford                                         | Yulia Startsev<br />Guy Bedford<br />Nicolò Ribaudo                     | <sub>[Testing plan][lazy-import-testplan]</sub>                     | <sub>[February&nbsp;2025][lazy-import-notes]</sub>         |
 | [`Upsert`][upsert]                                                             | Daniel Minor, Lauritz Thoresen Angeltveit, Jonas Haukenes, Sune Lianes, Vetle Larsen, Mathias Hop Ness | Daniel Minor                             | <sub>[Testing plan][upsert-testing-plan]</sub>                      | <sub>[July&nbsp;2025][upsert-notes]</sub>                  |
 | [Non-extensible Applies to Private][nonext-private]                            | Mark Miller<br />Shu-yu Guo<br />Chip Morningstar<br />Erik Marks | Mark Miller<br />Shu-yu Guo<br />Chip Morningstar<br />Erik Marks             | :question:                                                          | <sub>[September&nbsp;2025][nonext-private-notes]</sub>     |
 | [Joint Iteration][joint]                                                       | Michael Ficarra                                                         | Michael Ficarra                                                         | <sub>[Testing plan][joint-testplan]</sub>                           | <sub>November&nbsp;2025</sub>                              |
 
-
 ### Stage 2.7
 
 | Proposal                                                                       | Author                                                                  | Champion                                                                | <sub>Test262 Feature Flag</sub>                                     | <sub>Last Presented</sub>                                  |
@@ -178,7 +177,7 @@ Note that as part of the onboarding process your repository name may be normaliz
 [joint-testplan]: https://github.com/tc39/test262/issues/4112
 [dynamic-code-brand-checks]: https://github.com/tc39/proposal-dynamic-code-brand-checks
 [dynamic-code-brand-checks-notes]: https://github.com/tc39/notes/blob/HEAD/meetings/2019-12/december-5.md#dynamic-code-brand-checks-for-stage-2
-[error-iserror-tests]: https://github.com/tc39/test262/pull/4266
+[dynamic-code-brand-checks-no-tests]: https://github.com/tc39/test262/issues/4229
 [esm-phase]: https://github.com/tc39/proposal-esm-phase-imports
 [esm-phase-notes]: https://github.com/tc39/notes/blob/HEAD/meetings/2024-12/december-04.md#esm-phase-imports-for-stage-27
 [discards]: https://github.com/tc39/proposal-discard-binding