[HW][Seq] Allow typed attr to be an element of aggregate_constant and make seq.const_clock typed attr

[uenoku]

This fixes https://github.com/llvm/circt/issues/7716. Aggregate constant verifier rejects unknown attributes hence hw.aggregate_constant cannot be used for attributes defined by other dialects (in this case seq.const_clock) was rejected even when hw.aggregate_create allows users to create clock type arrays. This PR loosen the restriction by allowing TypedAttribute.

This PR also adds TypedAttrInterface to seq.const_clock and support its lowering.

[uenoku]

It doesn't introduce any new circular dependencies or anything like that right?

Yes, it uses TypedAttr instead of directly using seq.clock to avoid circular dependency between HW and Seq.