Bump golangci-lint to 2.7.2, enable modernize stringsbuilder (#36180)

Fixes were done automatically by `make lint-go-fix`. These modernize
fixes are very readable.

Co-authored-by: Giteabot <teabot@gitea.io>

.golangci.yml

@@ -111,9 +111,6 @@ linters:
         - require-error
     usetesting:
       os-temp-dir: true
-    modernize:
-      disable:
-        - stringsbuilder
     perfsprint:
       concat-loop: false
     govet: