[BUG] logs-otel-v1 has error syntax

[JongminChung]

Bug Description

I changed the template_type to use index-template when creating logs-tel-v1-index-template in the demo project.

• In this case, the path is '"type": "date_nanos".
• In addition, "ignore_above" should have an int, but the string type is coming.

Reproducing

Steps to recreate the behavior:

1. clone opentelemetry-demo
2. In the data-prepper pipeline code, add template_type: index-template

anticipated behavior

Screenshot
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Environment (please complete the following information):

• Operating system: docker container (amd64)
• Version: macostahoe 26.3

Additional Contexts
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