add "azure-asyncoperation" header into mgmt-core

[xiangyan99]

Description

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[Copilot]

Pull request overview

This PR adds support for the azure-asyncoperation header in ARM polling continuation tokens by overriding the _filter_headers_for_continuation_token method in both ARMPolling and AsyncARMPolling classes. The changes update the minimum azure-core version to 1.38.0 to use the new continuation token infrastructure.

Changes:

• Updated azure-core dependency from >=1.32.0 to >=1.38.0
• Added _filter_headers_for_continuation_token override in ARMPolling and AsyncARMPolling classes
• Created new _utils.py module with _filter_arm_headers function

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
sdk/core/azure-mgmt-core/setup.py	Bumped azure-core minimum version to 1.38.0 to support new continuation token format
sdk/core/azure-mgmt-core/azure/mgmt/core/polling/arm_polling.py	Added _filter_headers_for_continuation_token override and imported _filter_arm_headers utility
sdk/core/azure-mgmt-core/azure/mgmt/core/polling/async_arm_polling.py	Added _filter_headers_for_continuation_token override for async polling
sdk/core/azure-mgmt-core/azure/mgmt/core/polling/_utils.py	Created new utility module with ARM-specific header filtering logic
sdk/core/azure-mgmt-core/CHANGELOG.md	Added changelog entry documenting the bug fix

[pvaneck]

What do you think about calling the parent class _filter_headers_for_continuation_token here and starting from that in order to avoid importing internal objects (_LRO_HEADERS)? Then _ARM_LRO_HEADERS can just be ARM-specific headers (i.e. _ARM_LRO_HEADERS = frozenset(["azure-asyncoperation"]). No internal module imports needed. For example, something akin to:

filtered = super()._filter_headers_for_continuation_token()
filtered.update({header: headers[header] for header in _ARM_LRO_HEADERS if header in headers})
return filtered