Fail if no timebase is set

[bugadani]

Last few days I had various silent breakages because embassy-time was 1) removed 2) pinned to a specific version. In both cases, the version mismatch meant that no embassy-time-* feature was active, and embassy-time was initialized with the default 1MHz timer frequency.

I am not sure what we can do here, but I would like a solution that doesn't compile (or, at least warns) if esp-hal would fail to apply a timer frequency as it's an unfortunately difficult thing to debug.

[bugadani]

Maybe we could consider this a non-issue for now, now that the crate uses embassy-time 0.1.3.