[FW][FIX] sql_db: flush when no uid in environment

[fw-bot]

• A bug has been introduced by the PR [FIX] odoo: don't commit outside of a checked call #46719
  This issue prevented flushes to database when no uid is set in the
  current environment.
  This happens when database changes are made in auth="none" routes.
  In a MonoDB setup this was working because Odoo consider None, False as
  null and was always bound to a database.

  Nothing prevents to write null in the columns create_uid and
  write_uid in database.
  The PR that introduced the bug wanted to block the cases where
  uid is an instance of the class RequestUID to avoid Cannot adapt type errors.
  So testing that uid is an integer isn't enough.

  Two fixes were possible here, either check if uid is an instance
  of the class RequestUID or if it is either an integer, False or None.

  To avoid noise and imports from odoo, we test that uid is an instance
  of None.
  The case where it is False is already tested in the python code:

    isinstance(env.uid, int)

Description of the issue/feature this PR addresses:

Current behavior before PR:

Desired behavior after PR is merged:

--
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Forward-Port-Of: #48685

[fw-bot]

Ping @tbe-odoo
Cherrypicking e2504d9 of source #48685 failed

stdout:

On branch saas-13.2-13.0-flush-no-uid-fix-tbe-mk0m-fw
You are currently cherry-picking commit e2504d90e8f.

nothing to commit, working tree clean

stderr:

The previous cherry-pick is now empty, possibly due to conflict resolution.
If you wish to commit it anyway, use:

    git commit --allow-empty

Otherwise, please use 'git reset'

Either perform the forward-port manually (and push to this branch, proceeding as usual) or close this PR (maybe?).

In the former case, you may want to edit this PR message as well.

[tbe-odoo]

Forward ported manually