Fix #57418 - Assert that totalChars > leadingChars in preview options. And truncate match when it's > totalChars

Refresh comments panel when it comes into view again, fixes https://github.com/Microsoft/vscode-pull-request-github/issues/334

Adjust width of comment editor widget input box, fixes https://github.com/Microsoft/vscode-pull-request-github/issues/333

Fixes #56217

This reverts commit 1f7ce421.

* try to fix #57421

* remove native tab items

* another try

fixes #49039

fixes #54991

fixes #57489

This reverts commit 7df1ed4d.