Fix: Support Python-style multi-line values in .pypirc files

[omerzi]

• Add AllowPythonMultilineValues option to INI parser in loadOrCreatePypirc
• Add comprehensive test case TestConfigurePypircWithMultilineIndexServers
• Fixes 'key-value delimiter not found' error when parsing .pypirc files with multi-line index-servers format

Problem:
When users have .pypirc files with Python's standard multi-line format for index-servers:
[distutils]
index-servers =
repo1
repo2

The setup command would fail with: 'key-value delimiter not found: repo1'

Solution:
Enable AllowPythonMultilineValues option in the INI parser to properly handle Python-style configuration files where values can span multiple indented lines.

This ensures compatibility with .pypirc files created by other Python tools and maintains backward compatibility with single-line formats.

• All tests passed. If this feature is not already covered by the tests, I added new tests.
• All static analysis checks passed.
• Appropriate label is added to auto generate release notes.
• I used gofmt for formatting the code before submitting the pull request.
• PR description is clear and concise, and it includes the proposed solution/fix.

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