Add type: ignore for optional pysqlite3 and sqlean imports

These are alternative sqlite3 implementations that may not be installed.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <[email protected]>

Author: simonw

sqlite_utils/utils.py

@@ -15,14 +15,14 @@
 from . import recipes
 
 try:
-    import pysqlite3 as sqlite3  # noqa: F401
-    from pysqlite3 import dbapi2  # noqa: F401
+    import pysqlite3 as sqlite3  # type: ignore[import-not-found]  # noqa: F401
+    from pysqlite3 import dbapi2  # type: ignore[import-not-found]  # noqa: F401
 
     OperationalError = dbapi2.OperationalError
 except ImportError:
     try:
-        import sqlean as sqlite3  # noqa: F401
-        from sqlean import dbapi2  # noqa: F401
+        import sqlean as sqlite3  # type: ignore[import-not-found]  # noqa: F401
+        from sqlean import dbapi2  # type: ignore[import-not-found]  # noqa: F401
 
         OperationalError = dbapi2.OperationalError
     except ImportError: