[IMPR] use Site.file_extensions within checkimages.py and _upload.py

Note: fileextension property of siteinfo was introduced with mw 1.15
but the KeyError catch was inroduced to support mw 1.14, see T120080
and https://gerrit.wikimedia.org/r/c/pywikibot/core/+/223021/7

Change-Id: If21554ec7517eb7fe9624a02eabacbb30a078ce3
---
M pywikibot/specialbots/_upload.py
M scripts/checkimages.py
2 files changed, 15 insertions(+), 15 deletions(-)

diff --git a/pywikibot/specialbots/_upload.py b/pywikibot/specialbots/_upload.py
index c3f1c7a..045ac27 100644
--- a/pywikibot/specialbots/_upload.py
+++ b/pywikibot/specialbots/_upload.py
@@ -240,13 +240,7 @@
         # FIXME: these 2 belong somewhere else, presumably in family
         # forbidden characters are handled by pywikibot/page.py
         forbidden = ':*/\\'  # to be extended
-        try:
-            allowed_formats = self.target_site.siteinfo.get(
-                'fileextensions', get_default=False)
-        except KeyError:
-            allowed_formats = []
-        else:
-            allowed_formats = [item['ext'] for item in allowed_formats]
+        allowed_formats = self.target_site.file_extensions()
 
         # ask until it's valid
         first_check = True
diff --git a/scripts/checkimages.py b/scripts/checkimages.py
index 1c4e69e..06fafe9 100755
--- a/scripts/checkimages.py
+++ b/scripts/checkimages.py
@@ -1429,14 +1429,7 @@
 
         # Don't put "}}" here, please. Useless and can give problems.
         something = ['{{']
-        # Allowed extensions
-        try:
-            allowed_formats = self.site.siteinfo.get(
-                'fileextensions', get_default=False)
-        except KeyError:
-            allowed_formats = []
-        else:
-            allowed_formats = [item['ext'].lower() for item in allowed_formats]
+        allowed_formats = self.site.file_extensions()  # Allowed extensions
         brackets = False
         delete = False
         notification = None

