fix collapsed image preview that doesn't stay collapsed after posting a message in the channel (#6833)

webapp/utils/constants.jsx

@@ -951,7 +951,7 @@ export const Constants = {
     ANIMATION_TIMEOUT: 1000,
     SEARCH_TIMEOUT_MILLISECONDS: 100,
     DIAGNOSTICS_SEGMENT_KEY: 'fwb7VPbFeQ7SKp3wHm1RzFUuXZudqVok',
-    TEST_ID_COUNT: 10,
+    TEST_ID_COUNT: 0,
     CENTER: 'center',
     RHS: 'rhs',
     RHS_ROOT: 'rhsroot',