fix: handle git branch name with special chars correctly (#39483)

Fix the bugs:
* Commit graph page doesn't show
* PR command line instructions are wrong

---------

Co-authored-by: silverwind <me@silverwind.io>

services/repository/gitgraph/graph_models.go

@@ -216,7 +216,7 @@ func parseGitTime(timeStr string) time.Time {
 
 // NewCommit creates a new commit from a provided line
 func NewCommit(row, column int, line []byte) (*Commit, error) {
-	data := bytes.SplitN(line, []byte("|"), 5)
+	data := bytes.SplitN(line, []byte(gitLogGraphFormatSep), 5)
 	if len(data) < 5 {
 		return nil, fmt.Errorf("malformed data section on line %d with commit: %s", row, string(line))
 	}