UTableBlock was the only block component that never used the message
registry — it did not import it at all — so its search placeholder, row
count label, and Excel/CSV download tooltips stayed English in every
locale. All four now resolve through the registry, with en and ko tables.

The row count uses the registry's existing {name} interpolation
('{shown} / {total} Rows'), so no new message API was needed. Plural
forms are deliberately not handled: plural rules are locale specific and
adding an API for a single string is not warranted.

Adds browser regression tests covering the locale switch for all four
strings and asserting the interpolation actually substitutes — an
unsubstituted placeholder still renders a string and would otherwise
look like a pass.

Bumps to 0.11.8.