Styling should not depend on IDs to allow us to have multiple
searches in the page.
Precursor for wiring up search in the sticky header.
This also tweaks performance metrics to track separate metrics
for the sticky header search
Change-Id: I5b4192a8f5a9f95af26c1faf904f7cc994323518
- Apply aria-hidden to h3 in Menu template, ensuring the nav landmarks are still properly labeled, but no longer reading duplicate labels to screenreaders
- Remove "Navigation menu" h2 element, which is not needed as the nav landmarks are already labeled
- Remove searchbox h3 element, which is redundant with the search landmark
- Scope all changes to modern vector
Bug: T265993
Change-Id: I4e5da7a0699160fa57234bd126b75243e0157778
