[Snippets] LoopManager: error-prone code is removed (#31952)
### Details:
- *Removed `LoopInfo` constructor with vector of `ExpressionPort` as
entries/exits and the corresponding `mark_loop` helper in `LoopManager`,
since it is unsafe (it set `dim_idx=0` for all ports)*
- *Removed `dim_idx` from `mark_loop` helper with `LoopPort` entries and
exits, since LoopPort already contains `dim_idx` calue*
- *`LoopPort::create`: removed default value for `dim_idx`*
As a result of error-prone code with non-obvious logic removal, now it's
impossible to forget specifying `dim_idx` for some specific loop port
(otherwise, compilation fails) during loops creation, and there are no
ways to create loop from expression ports without loop ports creation.
### Tickets:
- *prerequisite for CVS-172631*
