fix: classify git failures on stderr, restrict migration failure detail (#39010)

Signed-off-by: silverwind <me@silverwind.io>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

modules/git/error.go

@@ -124,20 +124,3 @@ func (err *ErrPushRejected) GenerateMessage() {
 	}
 	err.Message = strings.TrimSpace(messageBuilder.String())
 }
-
-// ErrMoreThanOne represents an error if pull request fails when there are more than one sources (branch, tag) with the same name
-type ErrMoreThanOne struct {
-	StdOut string
-	StdErr string
-	Err    error
-}
-
-// IsErrMoreThanOne checks if an error is a ErrMoreThanOne
-func IsErrMoreThanOne(err error) bool {
-	_, ok := err.(*ErrMoreThanOne)
-	return ok
-}
-
-func (err *ErrMoreThanOne) Error() string {
-	return fmt.Sprintf("ErrMoreThanOne Error: %v: %s\n%s", err.Err, err.StdErr, err.StdOut)
-}