[JIRA] Add search/jql and search/approximate-count APIs support for Jira Cloud

[skumar36-atlassian]

Overview

This PR introduces two new functions specifically for Jira Cloud to replace deprecated search APIs:

enhanced_search_issues

• Leverages the new search/jql REST endpoint with nextPageToken-based pagination.
• Replaces the deprecated search API endpoints (GET/POST /rest/api/3/search).
• Supports fetching a limited set or all results based on the batch size parameter.
• Note: Atlassian will remove support for the old search API on May 1, 2025.

approximate_issue_count

• Uses the search/approximate-count API to retrieve an approximate count of issues for a given JQL query.
• Returns an integer count.

Changes

• Added enhanced_search_issues to perform nextPageToken-based pagination for Jira Cloud.
• Added approximate_issue_count to provide a quick issue count.
• Both functions are decorated with @cloud_api to ensure they’re used only on Jira Cloud.
• These updates ensure our library stays in line with Atlassian's deprecation roadmap, while Jira Server/Data Center users remain unaffected.

Testing & Limitations

• Manual Testing: Both functions have been manually tested against a Jira Cloud instance.
• Unit Tests: Due to challenges in configuring the test environment for Jira Cloud, full unit test coverage for these cloud-specific endpoints was not implemented. Further work is needed to establish a dedicated Jira Cloud test setup.

Migration & Impact

• Breaking Change:
  Atlassian has already deprecated the old search API endpoints. Jira Cloud users must migrate to enhanced_search_issues and approximate_issue_count to ensure continued compatibility beyond May 1, 2025.
• Jira Server/Data Center users are not affected and can continue using the existing APIs.

Additional Context

• This update is in line with Atlassian's push for more reliable and predictable APIs for Jira Cloud.
• For detailed information, please refer to Atlassian's deprecation roadmap and related documentation.
• Your feedback is welcome – please review and let me know if any modifications are required.

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Please review the changes and let me know if you have any questions or further suggestions. Thanks!

[skumar36-atlassian]

These workflows requires approval from a maintainer.
@Viktxrrr , @SuperWonjune , @aaronsewall , @bigmac7 , can you review this PR?