add property is readout twice while using screenreader (#1463)

* 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

* header text color changed to meet luminosity ratio requirement

* capacity calculator link has been added with underline on focus

* add property is readout twice while using screenreader

* Update fulldatatables.less

* Update queryBuilder.less

* Update TableEntity.tsx

* Update ThroughputInput.less

* Update ThroughputInput.tsx

* Update ThroughputInput.tsx

* Update ThroughputInput.test.tsx.snap

* Update QuickstartCarousel.tsx

* Update SplashScreen.tsx

src/Explorer/Panes/Tables/AddTableEntityPanel.tsx

@@ -295,8 +295,9 @@ export const AddTableEntityPanel: FunctionComponent<AddTableEntityPanelProps> =
             className="addButtonEntiy"
             tabIndex={0}
             onKeyPress={handlekeypressaddentity}
+            aria-label="Add Property"
           >
-            <Image {...imageProps} src={AddPropertyIcon} alt="Add Entity" />
+            <Image {...imageProps} src={AddPropertyIcon} alt="Add Property" />
             <Text className="addNewParamStyle">{getAddButtonLabel(userContext.apiType)}</Text>
           </Stack>
         )}

src/Explorer/Panes/Tables/__snapshots__/AddTableEntityPanel.test.tsx.snap

@@ -26,6 +26,7 @@ exports[`Excute Add Table Entity Pane should render Default properly 1`] = `
         className="panelMainContent"
       >
         <Stack
+          aria-label="Add Property"
           className="addButtonEntiy"
           horizontal={true}
           onClick={[Function]}
@@ -33,20 +34,21 @@ exports[`Excute Add Table Entity Pane should render Default properly 1`] = `
           tabIndex={0}
         >
           <div
+            aria-label="Add Property"
             className="ms-Stack addButtonEntiy css-53"
             onClick={[Function]}
             onKeyPress={[Function]}
             tabIndex={0}
           >
             <StyledImageBase
-              alt="Add Entity"
+              alt="Add Property"
               height={30}
               key=".0:$.0"
               src=""
               width={16}
             >
               <ImageBase
-                alt="Add Entity"
+                alt="Add Property"
                 height={30}
                 src=""
                 styles={[Function]}
@@ -335,7 +337,7 @@ exports[`Excute Add Table Entity Pane should render Default properly 1`] = `
                   }
                 >
                   <img
-                    alt="Add Entity"
+                    alt="Add Property"
                     className="ms-Image-image ms-Image-image--portrait is-notLoaded is-fadeIn image-55"
                     key="fabricImage"
                     onError={[Function]}