[MOB-12425] Properly Disable Network Interception with Patched XHR

[a7medev]

Description of the change

The current implementation of the network interceptor grabs the original XMLHttpRequest methods that we alter from the beginning (once you import instabug-reactnative) so that when the user wants to disable network interception/logging using NetworkLogger.setEnabled(false) it reassigns these methods back to their original version.
The fact that we grab original XHR methods on import means that any changes done by the user after this import will get ignored even after disabling network logging.

This PR modifies the XHR interceptor to get the original XMLHttpRequest methods when enabling it and not globally on import. This will enable users to patch XHR when network interception is disabled (which includes before Instabug.init and NetworkLogger.setEnabled(true) and after NetworkLogger.setEnabled(false)).

Type of change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Related issues

Fixes #981

Checklists

Development

• Lint rules pass locally
• The code changed/added as part of this pull request has been covered with tests

Code review

• This pull request has a descriptive title and information useful to a reviewer
• Issue from task tracker has a link to this pull request

[InstabugCI]

Coverage Report

Label	Coverage	Status
JavaScript	96.5%	✅
Android	47.8%	✅
iOS	39.0%	✅

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