Update `sourceTag` normalization to include `:` as an allowed character

[austin-denoble]

Problem

We want to allow : in sourceTags that are applied to user-agent headers on network requests.

Solution

• Update normalizeSourceTag function to allow : as an accepted character.
• Add new unit test permutation to validate functionality.

Type of Change

• [ ] Bug fix (non-breaking change which fixes an issue)
• [X] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] This change requires a documentation update
• [ ] Infrastructure change (CI configs, etc)
• [ ] Non-code change (docs, etc)
• [ ] None of the above: (explain here)

Test Plan

Test locally using the TyepScript repl with PINECONE_DEBUG and PINECONE_DEBUG_CURL to monitor network traffic:

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