Fix:Improve error handling when a request fails due to the persistent connection being expired #761

[avijitdas126]

Enhanced the do_api_query function with a retry mechanism (up to 3 attempts) for transient connection errors, configurable retry delays, and keep-alive headers. It resets the HTTP session on failures, differentiates between network errors and API errors, and maintains backward compatibility while improving reliability with optimized timeouts (90s for long-polling, 15s default).

• Implement retry mechanism (up to 3 attempts) for transient connection errors
• Add configurable retry delay and connection keep-alive headers
• Reset HTTP session on connection failures to ensure clean reconnect
• Differentiate between retryable network errors and API response errors
• Set appropriate timeouts (90s for long-polling, 15s default otherwise)
• Maintain backward compatibility while improving error resilience

Fixes: #761

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Self-review checklist

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[zulipbot]

Hello @avijitdas126, it seems like you have referenced #761 in your pull request description, but you have not referenced them in your commit message description(s). Referencing an issue in a commit message automatically closes the corresponding issue when the commit is merged, which makes the issue tracker easier to manage.

Please run git commit --amend in your command line client to amend your commit message description with Fixes #761..

An example of a correctly-formatted commit:

commit fabd5e450374c8dde65ec35f02140383940fe146
Author: zulipbot
Date:   Sat Mar 18 13:42:40 2017 -0700

    pull requests: Check PR commits reference when issue is referenced.

    Fixes #51.

To learn how to write a great commit message, please refer to our guide.

[zulipbot]

Hello @avijitdas126, it seems like you have referenced #761 in your pull request description, but you have not referenced them in your commit message description(s). Referencing an issue in a commit message automatically closes the corresponding issue when the commit is merged, which makes the issue tracker easier to manage.

Please run git commit --amend in your command line client to amend your commit message description with Fixes #761..

An example of a correctly-formatted commit:

commit fabd5e450374c8dde65ec35f02140383940fe146
Author: zulipbot
Date:   Sat Mar 18 13:42:40 2017 -0700

    pull requests: Check PR commits reference when issue is referenced.

    Fixes #51.

To learn how to write a great commit message, please refer to our guide.

[avijitdas126]

@timabbott could you please review this PR?