🚑 access_apps: fix error in Settings page

STEPS:
* install module_procurement_jit
* install access_apps
* open Settings menus

BEFORE:

```
Odoo Server Error
Traceback (most recent call last):
  File "/opt/odoo/custom/src/odoo/odoo/http.py", line 624, in _handle_exception
    return super(JsonRequest, self)._handle_exception(exception)
  File "/opt/odoo/custom/src/odoo/odoo/http.py", line 310, in _handle_exception
    raise pycompat.reraise(type(exception), exception, sys.exc_info()[2])
  File "/opt/odoo/custom/src/odoo/odoo/tools/pycompat.py", line 14, in reraise
    raise value
  File "/opt/odoo/custom/src/odoo/odoo/http.py", line 669, in dispatch
    result = self._call_function(**self.params)
  File "/opt/odoo/custom/src/odoo/odoo/http.py", line 350, in _call_function
    return checked_call(self.db, *args, **kwargs)
  File "/opt/odoo/custom/src/odoo/odoo/service/model.py", line 94, in wrapper
    return f(dbname, *args, **kwargs)
  File "/opt/odoo/custom/src/odoo/odoo/http.py", line 339, in checked_call
    result = self.endpoint(*a, **kw)
  File "/opt/odoo/custom/src/odoo/odoo/http.py", line 915, in __call__
    return self.method(*args, **kw)
  File "/opt/odoo/custom/src/odoo/odoo/http.py", line 515, in response_wrap
    response = f(*args, **kw)
  File "/opt/odoo/auto/addons/web/controllers/main.py", line 1327, in call_kw
    return self._call_kw(model, method, args, kwargs)
  File "/opt/odoo/auto/addons/web/controllers/main.py", line 1319, in _call_kw
    return call_kw(request.env[model], method, args, kwargs)
  File "/opt/odoo/custom/src/odoo/odoo/api.py", line 387, in call_kw
    result = _call_kw_multi(method, model, args, kwargs)
  File "/opt/odoo/custom/src/odoo/odoo/api.py", line 374, in _call_kw_multi
    result = method(recs, *args, **kwargs)
  File "/opt/odoo/custom/src/odoo/odoo/models.py", line 6240, in onchange
    record[name] = value
  File "/opt/odoo/custom/src/odoo/odoo/models.py", line 5740, in __setitem__
    return self._fields[key].__set__(self, value)
  File "/opt/odoo/custom/src/odoo/odoo/fields.py", line 1082, in __set__
    self.write(new_records, value)
  File "/opt/odoo/custom/src/odoo/odoo/fields.py", line 953, in write
    cache_value = self.convert_to_cache(value, records)
  File "/opt/odoo/custom/src/odoo/odoo/fields.py", line 2262, in convert_to_cache
    raise ValueError("Wrong value for %s: %r" % (self, value))
ValueError: Wrong value for res.config.settings.module_procurement_jit: 1
```

AFTER: no errors

WHY: since Odoo 13 it has to be string: odoo/odoo@a0e05e2

Author: yelizariev

access_apps/doc/changelog.rst

@@ -1,6 +1,7 @@
 `2.0.0`
 -------
 - **Fix:** restore original access rights on uninstallation
+- **Fix:** error in Settings menu when some modules are installed
 
 `1.3.3`
 -------

access_apps/models/res_config.py

@@ -33,7 +33,7 @@ def default_get(self, fields):
         for name, module in classified["to_uninstall"]:
             res[name] = module.state in ("installed", "to install", "to upgrade")
             if self._fields[name].type == "selection":
-                res[name] = int(res[name])
+                res[name] = str(int(res[name]))
 
         return res