[8.x](backport #41970) [filebeat][gcs] - Removed bucket_timeout config option and replaced bucket context with parent program context

[mergify]

Type of change

• Deprecation
• Docs

Proposed commit message

• WHAT: Removed bucket_timeout config option and replaced bucket context with parent program context
• WHY: The bucket_timeout option was used to specify the timeout for the individual bucket operations. This option was
  difficult to understand in its effects resulting in malconfiguration leading to processing timeouts and context cancellation, ultimately causing gaps in the ingested data. To avoid this, the bucket_timeout option has been removed. The input now uses the parent program context to handle the contexts for bucket operations.

Checklist

• My code follows the style guidelines of this project
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have made corresponding change to the default configuration files
• I have added tests that prove my fix is effective or that my feature works
• I have added an entry in CHANGELOG.next.asciidoc or CHANGELOG-developer.next.asciidoc.

Disruptive User Impact

Since it is a config option that has not impact on ingested data, this removal should not have any user impact.

Author's Checklist

• [ ]

How to test this PR locally

Related issues

• Relates [Meta][GCS] - Improvements and addition of new features to the GCS input #41107

Use cases

Screenshots

Logs

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This is an automatic backport of pull request #41970 done by [Mergify](https://mergify.com).

[botelastic]

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[ShourieG]

/test