CG-1234: Add comments and reviews to GithubViewPRTool

[codegen-sh]

This PR adds support for including comments and reviews in the GithubViewPRTool output.

Changes:

1. Updated the ViewPRObservation class to include fields for comments and reviews
2. Modified the get_modified_symbols_in_pr method in the Codebase class to fetch and return PR comments and reviews
3. Fixed a typo in the variable name (moddified_symbols -> modified_symbols)

Implementation Details:

• Comments include both issue comments and review comments (comments on specific lines)
• Each comment includes metadata like user, body, creation date, etc.
• Reviews include metadata like user, body, state, etc.

Fixes the issue mentioned in Slack: https://codegencommunity.slack.com/archives/C08JKKP35PT/p1742572530749669?thread_ts=1742408765.927599&cid=C08JKKP35PT