support accessing the store in `bindgen!` in `no_std` contexts for synchronous imports

#### Feature

#11628 adds support for accessing the store in `bindgen!`-generated import function in traits. This is great but currently even when generating with `async: false` this is gated behind the `component-model-async` feature which is itself requires `std`. The proposed feature would be to un-gate the improvements of the aforementioned PR #11628 for synchronous imports.

#### Benefit
This would allow users using `wasmtime` in `no_std` embedded systems to also access the store in their generated import functions.

#### Implementation

I don't know all of the implications but the discussions in #11590 suggest that un-gating the `Access` struct would be a start.

#### Alternatives

Without this feature, `no_std` users that need/want to access the store in their imports have to do so outside of the component-model.