R1:1059fae6c9b6

Set an explicit default value for the bulk action control

Summary:
Ref T13025. See <https://discourse.phabricator-community.org/t/bulk-edit-no-actions-available/1011/1>.

I'm not sure if this is what the user is seeing, but in Chrome, the `<select />` does not automatically get set to the first valid value like it does in Safari.

Set it to the first valid value explicitly.

Test Plan: In Chrome, bulk editor previously hit a JS error when trying to read a bad action off the `<select />`. After patch, bulk…