libsql-sqlite3: Fix error reporting in WAL API

We need to call sqlite3Error() to report anything but "not an error" to
callers.

Author: penberg

libsql-sqlite3/src/main.c

@@ -2470,6 +2470,7 @@ int libsql_wal_frame_count(
   sqlite3_mutex_enter(db->mutex);
   pPager = sqlite3BtreePager(db->aDb[0].pBt);
   rc = sqlite3PagerWalFrameCount(pPager, pnFrame);
+  sqlite3Error(db, rc);
   sqlite3_mutex_leave(db->mutex);
   return rc;
 #endif
@@ -2498,6 +2499,7 @@ int libsql_wal_get_frame(
   sqlite3_mutex_enter(db->mutex);
   pPager = sqlite3BtreePager(db->aDb[0].pBt);
   rc = sqlite3PagerWalReadFrameRaw(pPager, iFrame, pBuf, nBuf);
+  sqlite3Error(db, rc);
   sqlite3_mutex_leave(db->mutex);
 
   return rc;
@@ -2527,6 +2529,7 @@ int libsql_wal_insert_begin(sqlite3 *db) {
     goto out_unlock;
   }
 out_unlock:
+  sqlite3Error(db, rc);
   sqlite3_mutex_leave(db->mutex);
   return rc;
 }
@@ -2542,6 +2545,7 @@ int libsql_wal_insert_end(sqlite3 *db) {
     goto out_unlock;
   }
 out_unlock:
+  sqlite3Error(db, rc);
   sqlite3_mutex_leave(db->mutex);
   return rc;
 }
@@ -2573,6 +2577,7 @@ int libsql_wal_insert_frame(
     goto out_unlock;
   }
 out_unlock:
+  sqlite3Error(db, rc);
   sqlite3_mutex_leave(db->mutex);
 
   return rc;