defect2270063 (#1477)

* arialabel has been added to close button of invitational youtube video

* heading role has been addedd and tag has been changed to h1

* outline has been restored to choose columns link in entities page

* Update QuickstartCarousel.tsx

* Update SplashScreen.tsx

* Update TableEntity.tsx

* outline for edit entity has been added on focus

* keyboard accessibility added to rows in table entities

* learn more link under analytical store

* Column header is populated with text

* aria label has been changed for  the screen readers to read placeholder text along with label text

* role and alt text has been added to presentation images

* Update queryBuilder.less

* Update TableEntity.tsx

* Update ThroughputInputAutoPilotV3Component.tsx

* Update ThroughputInputAutoPilotV3Component.tsx

* Update ThroughputInputAutoPilotV3Component.test.tsx.snap

* Update ThroughputInput.less

* Update DataTableBindingManager.ts

* Update AddCollectionPanel.test.tsx.snap

* Update PanelComponent.less

* Update AddCollectionPanel.tsx

src/Explorer/Tabs/QueryTablesTab.html

@@ -77,7 +77,13 @@
           <div class="addClause" data-bind=" ">
             <div class="addClause-heading">
               <span class="clause-table addClause-title">
-                <img class="addclauseProperty-Img" style="margin-bottom: 5px" src="/Add-property.svg" />
+                <img
+                  class="addclauseProperty-Img"
+                  style="margin-bottom: 5px"
+                  src="/Add-property.svg"
+                  alt="Add new Clause"
+                  role="presentation"
+                />
                 <span style="margin-left: 5px" data-bind="text: addNewClauseLine"></span>
               </span>
             </div>
@@ -119,7 +125,12 @@
             aria-label="Show top results"
           />
           <div role="alert" aria-atomic="true" class="inline-div" data-bind="visible: isExceedingLimit">
-            <img class="advanced-options-icon" src="/QueryBuilder/StatusWarning_16x.png" />
+            <img
+              class="advanced-options-icon"
+              src="/QueryBuilder/StatusWarning_16x.png"
+              alt="Warning"
+              role="presentation"
+            />
             <span data-bind="text: topValueLimitMessage"></span>
           </div>
         </div>