Postgres: Config diagnostics / logging update (#105666)

* config diagnostics update

* update tests

* fix typo

pkg/tsdb/grafana-postgresql-datasource/sqleng/handler_checkhealth.go

@@ -81,8 +81,8 @@ func ErrToHealthCheckResult(err error) (*backend.CheckHealthResult, error) {
 			details["verboseMessage"] = pqErr.Message
 		}
 	}
-	if errors.Is(err, ErrInvalidPortSpecified) {
-		res.Message = fmt.Sprintf("Connection string error: %s", ErrInvalidPortSpecified.Error())
+	if errors.Is(err, ErrParsingPostgresURL) {
+		res.Message = fmt.Sprintf("Connection string error: %s", ErrParsingPostgresURL.Error())
 		if unwrappedErr := errors.Unwrap(err); unwrappedErr != nil {
 			details["verboseMessage"] = unwrappedErr.Error()
 		}