MSSQL: Minor refactor (#113976)

* Moving things around

* Copy parseURL function to where it's used

* Update test

* Remove experimental-strip-types

* Revert "Remove experimental-strip-types"

This reverts commit 70fbc1c0cd.

* Trigger build

pkg/api/pluginproxy/ds_proxy_test.go

@@ -886,7 +886,7 @@ func TestNewDataSourceProxy_MSSQL(t *testing.T) {
 			description: "Invalid ODBC URL",
 			url:         `localhost\instance::1433`,
 			err: datasource.URLValidationError{
-				Err: errors.New(`unrecognized MSSQL URL format: "localhost\\instance::1433"`),
+				Err: errors.New(`unrecognized URL format: "localhost\\instance::1433"`),
 				URL: `localhost\instance::1433`,
 			},
 		},