Sampath accessibility sev 2 2 (#1404)

* autoscale and manual radiobuutton fixes

* alt text attribute for images

* Revert "alt text attribute for images"

This reverts commit 5a660551c6.

* alt text for decorative images

* sev2 accessibilitydefects in data explorer

* Revert "sev2 accessibilitydefects in data explorer"

This reverts commit b84d5b572c.

* Sev2 accessibilitydefects

* Revert "Sev2 accessibilitydefects"

This reverts commit a4e60f106c.

* accessibilitydefects-data explorer

* Accessibility sev-2 defects-2

* corrections for 2278347,2278096 and fix for 2264174

* color for placeholder changed to 767474, margin is set to accommodate height between treeheader elements

* padding added for databaseheader, removed margin and restored padding to treenodeheader

src/Explorer/Panes/AddCollectionPanel.tsx

@@ -403,6 +403,7 @@ export class AddCollectionPanel extends React.Component<AddCollectionPanelProps,
                 content={`Unique identifier for the ${getCollectionName().toLocaleLowerCase()} and used for id-based routing through REST and all SDKs.`}
               >
                 <Icon
+                  role="button"
                   iconName="Info"
                   className="panelInfoIcon"
                   tabIndex={0}

src/Explorer/Panes/__snapshots__/AddCollectionPanel.test.tsx.snap

@@ -172,6 +172,7 @@ exports[`AddCollectionPanel should render Default properly 1`] = `
             ariaLabel="Unique identifier for the container and used for id-based routing through REST and all SDKs."
             className="panelInfoIcon"
             iconName="Info"
+            role="button"
             tabIndex={0}
           />
         </StyledTooltipHostBase>