Stabilize module extension/extensionauth

[mx-psi]

Before stabilizing a module, an approver or maintainer must make sure that the following criteria have been met for at least two successive minor version releases (regardless of when this issue was opened):

• No open issues or PRs in the module that would require breaking changes
• No TODOs in the module code that would require breaking changes
• No deprecated symbols in the module
• No symbols marked as experimental in the module
• The module follows the Coding guidelines

Please also make sure to publicly announce our intent to stabilize the module on:

• The #otel-collector CNCF Slack Channel
  • https://cloud-native.slack.com/archives/C01N6P7KR6W/p1724941491032679
• The #opentelemetry CNCF Slack channel
  • Linked to above message
• A Collector SIG meeting (if unable to attend, just add to the agenda)
  • Added to 2024-09-04 meeting notes

To help other people verify the above criteria, please link to the announcement and other links used to complete the above in a comment on this issue.

Once all criteria are met, close this issue by moving this module to the stable module set.

[mx-psi]

Blocked by stabilizing extension