Simplify MatchUserWithAllowedRegexes

This used to return an error back when it was dealing with wildcards
(which may or may not have compiled to a valid regex).

But it now deals with pre-compiled regexes and has no chance of failing,
so we need no `error` returns.

utils/user_test.go

@@ -202,10 +202,7 @@ func TestMatch(t *testing.T) {
 					t.Error(err)
 				}
 
-				actualResult, err := MatchUserWithAllowedRegexes(testData.checkedValue, *allowedUserRegexes)
-				if err != nil {
-					t.Error(err)
-				}
+				actualResult := MatchUserWithAllowedRegexes(testData.checkedValue, *allowedUserRegexes)
 
 				if actualResult == testData.expectedResult {
 					return