[TESTS] MockVariable temporarily replaces a global value

defer test.MockVariable(&variable, 1234)()

(cherry picked from commit 9c78752444c2411f20e72b96b7b4fdf5359099d5)
(cherry picked from commit 8ab559df0d57a17a0ea73bd3676f40a523a15ab6)
(cherry picked from commit 2e7fe1ec9566e4840992e4049d8349873b7334ee)
(cherry picked from commit f9618b8896)

Conflicts:
	modules/test/utils.go
	https://codeberg.org/forgejo/forgejo/issues/1219

modules/test/utils.go

@@ -22,3 +22,11 @@ func MockVariableValue[T any](p *T, v T) (reset func()) {
 	*p = v
 	return func() { *p = old }
 }
+
+func MockVariable[T any](variable *T, mock T) func() {
+	original := *variable
+	*variable = mock
+	return func() {
+		*variable = original
+	}
+}