[FIX+IMP] account_financial_report: data can be None + no context mangling

Depending on the calling method, data can be something different from a dictionary
(like `None` if no keyword argument is provided), so this will crash. Example:
mis_builder is crashing in its tests.

We prevent that checking for a falsy value before trying to access the dictionary.

We also avoid context mangling for non AFR reports (those without the key
`account_financial_report_lang` in the dictionary), not callign to `with_context`
in that case.

account_financial_report/__manifest__.py

@@ -5,7 +5,7 @@
 # License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl.html).
 {
     "name": "Account Financial Reports",
-    "version": "13.0.1.3.1",
+    "version": "13.0.1.3.2",
     "category": "Reporting",
     "summary": "OCA Financial Reports",
     "author": "Camptocamp SA,"