[FIX] web_editor: fix resizing columns out of parent

Before this commit, it was possible to resize a column so that it
overflows the right border of the row.

Steps to reproduce the bug:
  1. In website edit mode, drop a `media list` snippet in the page.
  2. Select a column.
  3. Resize the column by dragging its left side to the right to make it
  smaller.
  4. Drag its right side to make it bigger and go until the edge of the
  editor => The column overflows and ends outside of the content zone.

This commit prevents the column from overflowing when it has an offset.

task-2837361

closes odoo/odoo#108022

X-original-commit: 2d825e02
Signed-off-by: Bojabza Soukéina (sobo) <sobo@odoo.com>