feat: adds option to force update new branch in contents routes (#35592)

Allows users to specify a "force" option in API /contents routes when
modifying files in a new branch. When "force" is true, and the branch
already exists, a force push will occur provided the branch does not
have a branch protection rule that disables force pushing.

This is useful as a way to manage a branch remotely through only the
API. For example in an automated release tool you can pull commits,
analyze, and update a release PR branch all remotely without needing to
clone or perform any local git operations.

Resolve #35538

---------

Co-authored-by: Rob Gonnella <rob.gonnella@papayapay.com>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

.gitignore

@@ -25,6 +25,9 @@ __debug_bin*
 # Visual Studio
 /.vs/
 
+# mise version managment tool
+mise.toml
+
 *.cgo1.go
 *.cgo2.c
 _cgo_defun.c
@@ -121,4 +124,3 @@ prime/
 /AGENT.md
 /CLAUDE.md
 /llms.txt
-