[darjeeling] Block level DV/test bench failures

The Darjeeling DV environments are currently unusable/completely broken for the following IPs at block level:

1. ~~RV_DM - See PR #26791 Basic smoke test passes using DMI interface (Darjeeling) and does not appear to interfere with JTAG interface (Earl Grey)~~
2. ~~clkmgr - The DV environment has not been templated to account for the set of clocks (peripheral and particularly measured clocks) differing between Darjeeling and Earl Grey. This is quite a body of work; [draft PR](https://github.com/lowrisc/opentitan/pull/26783) under construction.~~
3. pwrmgr - The block level DV environment fails with the same error on all tests; tracked in issue [#22710](https://github.com/lowrisc/opentitan/issues/22710) as annotated in ..dv/tb.sv. This has been addressed at top level and similar behavior must be implemented at block level. It is possible that there are other issues relating to the pwrmgr block now being an ipgen block.

@andreaskurth, @johngt for awareness.