Fix opening infinite db editor tabs from same db

If a db_map is already opened in a db editor, new tabs
with the same db_map won't be opened anymore. Instead
the one already open is brought up. If however the
same db_map is opened in a new window, it is allowed
to open.

Re spine-tools/Spine-Toolbox#2435

spinedb_api/db_mapping.py

@@ -211,7 +211,7 @@ def _make_codename(self, codename):
         if not self.sa_url.drivername.startswith("sqlite"):
             return self.sa_url.database
         if self.sa_url.database is not None:
-            return os.path.basename(self.sa_url.database)
+            return os.path.splitext(os.path.basename(self.sa_url.database))[0]
         hashing = hashlib.sha1()
         hashing.update(bytes(str(time.time()), "utf-8"))
         return hashing.hexdigest()