perf(logs): avoid string allocation when no parameters are passed

[Flash0ver]

Noticed during getsentry/sentry-unity#2389.

Avoid a string allocation when there are no parameters that the template string should be formatted with.

TODO:

• after v6
• a quick benchmark could not confirm the performance improvement ... need to follow up after v6 release

[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

### Performance

- avoid string allocation when no parameters are passed ([#4697](https://github.com/getsentry/sentry-dotnet/pull/4697))

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

Generated by 🚫 dangerJS against 09ad86b