Bugfix/15590 field layout designer col heights

[i-just]

Description

At certain widths, the field layout designer was assigning tab heights incorrectly. This happened because the tab width in v5 is greater (288px) than in v4 (264px), but the grid size used by the js wasn’t updated.

Replication steps:

• set up an entry type that has at least 3 tabs; tab 1 should have more fields added to it than the others (e.g. 5), and tabs 2 and 3 should have only one field each;
• set the browser window width to 960px (height, e.g. 1000px) and edit entry type on a standalone page (not via slideout) - notice that tab 2 has the same height as tab 1, even though it has considerably fewer fields;
• set the browser window width to 1660px (height, e.g. 1000px) and edit a section that has this entry type assigned; double-click the entry type so that we can edit it in a slideout; once the slideout launches, close the sidebar and notice that the tabs look good, but if you try to add a new field or UI element to the first tab, the second tab height will be updated to be the same as the first’s;
• try the same with this PR, and in both cases, the issue will be resolved

Related issues

#15590