fix(web): avoid error if timerid not valid

Relates to #5904.

If a call to api.keyman.com takes longer than 10 seconds, the timerid
would no longer be valid, even if the call returns successfully. This
threw a cascade of errors.

There was a secondary issue where keymanweb.com was passing in an
invalid timerid, causing the same error cascade. This is fixed in
keymanapp/keymanweb.com#38.