Various ARIA a11y fixes.

Notate RightPanel tabs.
Shorten Screen Reader queues.
Make AccessibleTooltipButton screen reader friendly
Flatten DOM for Sticker button using React Fragments

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

src/components/views/rooms/ThirdPartyMemberInfo.js

@@ -121,7 +121,7 @@ export default class ThirdPartyMemberInfo extends React.Component {
 
         // We shamelessly rip off the MemberInfo styles here.
         return (
-            <div className="mx_MemberInfo">
+            <div className="mx_MemberInfo" role="tabpanel">
                 <div className="mx_MemberInfo_name">
                     <AccessibleButton className="mx_MemberInfo_cancel"
                         onClick={this.onCancel}