Partly fix incorrect code review comment line number

[yp05327]

A quick fix for #30844

The solution is updating the comment line when load diff.
We will get the diffs from the commit SHA of this comment when it is created to the current PR's commit SHA.
Then we can get the correct line number. (whether the commented line is deleted or becomes to another line)

But this will increase the I/O cost.

TODO

• when add comments still have a bug: hidden comments will display
• fix test

[skarndev]

Why closed?

[yp05327]

1. The solution of this PR is not good enough. We need to update the line when user pushes new commits.
2. I have tried to rewrite a new one. But I notice that the current DB design is not good enough. (It is related to 3) We need to discuss it.
3. There's no template ( a correct rule to display these line numbers ), as GitHub also have some similar bugs, so we should decide them first. e.g.

• When should we remove the comment ? Do we need to recover the comment after user deleted and re-added the changes again. e.g. line 6 + aaa there's a comment, then the next commit removed this line, so this comment will also be removed, and then the next next commit added this change back ( same line number or different line number ), do we need to show this comment again or not. And also another question : should this comment keeping outdated status?
• How to pin the line number to the comment, IMO, we need to save the line number when the comment created ( this is what we did ), and also the line number of the latest status.