v3.25.1 breaks store direct property assignment

[trmcnvn]

PR #5390 introduced a bug where upon direct property assignment on a store it will overwrite the entire store's value.

Reproduction
https://svelte.dev/repl/d9156516adcd4775b89112b65a071ef4?version=3.25.1

3.25.0 Compiler Output

set_store_value(store, $store.data = [1, 2, 3, 4], $store);

3.25.1 Compiler Ouput

set_store_value(store, $store.data = [1, 2, 3, 4]);

[Conduitry]

This has been fixed in 3.26.0 - https://svelte.dev/repl/d9156516adcd4775b89112b65a071ef4?version=3.26.0