Loki: Fix e2e flakiness (#69441)

fix loki e2e test flakiness by waiting for requests to finish

e2e/various-suite/loki-query-builder.spec.ts

@@ -31,14 +31,22 @@ describe('Loki query builder', () => {
   });
 
   it('should be able to use all modes', () => {
-    e2e().intercept(/labels?/, (req) => {
-      req.reply({ status: 'success', data: ['instance', 'job', 'source'] });
-    });
+    e2e()
+      .intercept(/labels\?/, (req) => {
+        req.reply({ status: 'success', data: ['instance', 'job', 'source'] });
+      })
+      .as('labelsRequest');
 
     e2e().intercept(/series?/, (req) => {
       req.reply({ status: 'success', data: [{ instance: 'instance1' }] });
     });
 
+    e2e()
+      .intercept(/values/, (req) => {
+        req.reply({ status: 'success', data: ['instance1', 'instance2'] });
+      })
+      .as('valuesRequest');
+
     // Go to Explore and choose Loki data source
     e2e.pages.Explore.visit();
     e2e.components.DataSourcePicker.container().should('be.visible').click();
@@ -62,13 +70,16 @@ describe('Loki query builder', () => {
     e2e().contains(MISSING_LABEL_FILTER_ERROR_MESSAGE).should('be.visible');
 
     // Add labels to remove error
-    e2e.components.QueryBuilder.labelSelect().should('be.visible').click().type('instance{enter}');
+    e2e.components.QueryBuilder.labelSelect().should('be.visible').click();
+    // wait until labels are loaded and set on the component before starting to type
+    e2e().wait('@labelsRequest');
+    e2e().wait(100);
+    e2e.components.QueryBuilder.labelSelect().type('instance{enter}');
     e2e.components.QueryBuilder.matchOperatorSelect().should('be.visible').click().type('=~{enter}');
-    e2e.components.QueryBuilder.valueSelect()
-      .should('be.visible')
-      .click()
-      .type('instance1{enter}')
-      .type('instance2{enter}');
+    e2e.components.QueryBuilder.valueSelect().should('be.visible').click();
+    e2e().wait('@valuesRequest');
+    e2e().wait(100);
+    e2e.components.QueryBuilder.valueSelect().type('instance1{enter}').type('instance2{enter}');
     e2e().contains(MISSING_LABEL_FILTER_ERROR_MESSAGE).should('not.exist');
     e2e().contains(finalQuery).should('be.visible');