fix suggestion realignment logic for rebased commits

Summary:
Context: Before the suggestion realignment logic takes the commit head's content and compare it to the text in the VS Code editor.

However when author rebased, the commit head's content could potentially change. Which won't reflect the SuggestedCode's line number.

Solution: Instead of using the commitHeadHash, we use the commit hash for the Code Patch (which reflects the hash when the suggested change was made).

We then compare that text with the editor content to realign or apply changes.

Differential Revision: D65914471

fbshipit-source-id: e4431b4a1717ddbd199217300407d0acdbba87f6

addons/isl/src/types.ts

@@ -97,6 +97,7 @@ export type SuggestedChange = {
   id?: string;
   codePatchSuggestionID?: string;
   status?: CodePatchSuggestionStatus;
+  commitHashBefore?: string;
   patch?: ParsedDiff;
   oldPath?: string;
   currentPath?: string;