Loki: Fix issues with using query patterns (#50414)

* WIP

* Loki: Fix running of query patterns

* Remove console.log

* Add test

* Update empty line filter test

public/app/plugins/datasource/loki/querybuilder/parsing.test.ts

@@ -374,6 +374,29 @@ describe('buildVisualQueryFromString', () => {
     );
   });
 
+  it('parses metrics query with vector aggregation with number', () => {
+    expect(
+      buildVisualQueryFromString('topk(10, sum(count_over_time({app="frontend"} | logfmt | __error__=`` [5m])))')
+    ).toEqual(
+      noErrors({
+        labels: [
+          {
+            op: '=',
+            value: 'frontend',
+            label: 'app',
+          },
+        ],
+        operations: [
+          { id: 'logfmt', params: [] },
+          { id: '__label_filter_no_errors', params: [] },
+          { id: 'count_over_time', params: ['5m'] },
+          { id: 'sum', params: [] },
+          { id: 'topk', params: [10] },
+        ],
+      })
+    );
+  });
+
   it('parses template variables in strings', () => {
     expect(buildVisualQueryFromString('{instance="$label_variable"}')).toEqual(
       noErrors({