fix: Renamed ISession to ISentrySession

[bitsandfoxes]

We missed ISession when preparing the SDK to add itself to the global usings.

Relates to #3105

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (66920cd) 76.86% compared to head (fef4df2) 76.77%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3110      +/-   ##
==========================================
- Coverage   76.86%   76.77%   -0.09%     
==========================================
  Files         357      357              
  Lines       13466    13466              
  Branches     2671     2671              
==========================================
- Hits        10351    10339      -12     
- Misses       2435     2447      +12     
  Partials      680      680              

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[github-actions]

	Fails
🚫	Please consider adding a changelog entry for the next release.

Instructions and example for changelog

Please add an entry to CHANGELOG.md to the "Unreleased" section. Make sure the entry includes this PR's number.

Example:

## Unreleased

- Renamed `ISession` to `ISentrySession` ([#3110](https://github.com/getsentry/sentry-dotnet/pull/3110))

If none of the above apply, you can opt out of this check by adding #skip-changelog to the PR description.

Generated by 🚫 dangerJS against fef4df2