Remove "or keyword" from Library search bar

[emmastephenson]

What needs to be done

Change the placeholder text in the eCR Library search bar to read "Search by patient" (removing the "or keyword" that is currently present).

Why it needs to be done

Keyword search isn't actually supported in the Viewer yet, so this instruction is confusing to end users.

Acceptance Criteria

• Placeholder text on the eCR Library search reads simply "Search by patient"

Technical Notes

n/a

Additional context

n/a