refactor: Extract MSColab dialogs to separate modules

[Sumit6307]

Purpose of PR?:
This PR refactors mslib/msui/mscolab.py to address the "God Class" maintainability issue. It extracts the MSColab_ConnectDialog and MSColab_OperationArchiveBrowser classes into their own dedicated modules (mslib/msui/mscolab_connect_dialog.py and mslib/msui/mscolab_archive_browser.py). This separation significantly reduces the size of mscolab.py and improves code organization without changing functionality.

Does this PR introduce a breaking change?
No

If the changes in this PR are manually verified, list down the scenarios covered::

• Verified syntax correctness of new modules using python -m py_compile.
• Verified that mslib/msui/mscolab.py correctly imports and initializes the extracted classes.
• Confirmed that the refactoring preserves the original class signatures and inheritance.

Additional information for reviewer? :
This is part of a larger effort to improve the modularity of the MSColab client. By isolating UI components, we pave the way for better testability and future separation of network logic.

Does this PR results in some Documentation changes?
No

Checklist:

• Bug fix. Fixes #
• New feature (Non-API breaking changes that adds functionality)
• PR Title follows the convention of <type>: <subject>
• Commit has unit tests

[Sumit6307]

Hi @ReimarBauer , please have a look at this PR. Thanks!

[ReimarBauer]

please adjust the year to -2026

[ReimarBauer]

please adjust the year to -2026

[ReimarBauer]

We usually describe a task or project within an issue in our project, and then discuss it there. Once it's been assigned, we start working on it.

I noticed you were interested in Google Summer of Code (GSoC). We won’t be taking part this year.

[ReimarBauer]

see comments and result of linting tests.