Replace interface{} with any (#25686)

Result of running `perl -p -i -e 's#interface\{\}#any#g' **/*` and `make fmt`.

Basically the same [as golang did](https://github.com/golang/go/commit/2580d0e08d5e9f979b943758d3c49877fb2324cb).

models/unittest/testdb.go

@@ -37,7 +37,7 @@ func FixturesDir() string {
 	return fixturesDir
 }
 
-func fatalTestError(fmtStr string, args ...interface{}) {
+func fatalTestError(fmtStr string, args ...any) {
 	_, _ = fmt.Fprintf(os.Stderr, fmtStr, args...)
 	os.Exit(1)
 }