terminology: recalculate textgrid size when config is updated

Summary:
When configuration (font size, face..) was changed, textgird size was not recalulated properly.

Fixes T945

Test Plan: terminology -> maximize window -> font change (size) -> check whether max col/row are fit on window size

Reviewers: raster, cedric, billiob

Reviewed By: billiob

CC: seoz

Maniphest Tasks: T945

Differential Revision: https://phab.enlightenment.org/D772
fix typo