When changing the number of columns of a snippet, the history was
recorded too many times and at wrong moments, resulting in a mess of
undos to trigger before restoring the original column state.
The issue was due a combination of dead code and the fact that
`_updateColumnCount` triggered `remove_snippet` for each of its columns
while `remove_snippet` in turn triggered a history step at every
execution.
This fixes it by removing the dead code, replacing it where necessary
with a call to the editor's `historyStep` method, and adding an option
to `remove_snippet` so its triggering of a history step can be bypassed.
closesodoo/odoo#70932
X-original-commit: 877e5c807087afed880aeba3eab79def3a7b583c
Signed-off-by: David Monjoie (dmo) <dmo@odoo.com>