isisd: fix router capability TLV parsing issues

isisd: fix router capability TLV parsing issues

isis_tlvs.c would fail at multiple places if incorrect TLVs were
received causing stream assertion violations.
This patch fixes the issues by adding missing length checks, missing
consumed length updates and handling malformed Segment Routing subTLVs.

Signed-off-by: Juraj Vijtiuk <juraj.vijtiuk@sartura.hr>
Small adjustments by Igor Ryzhov:
- fix incorrect replacement of srgb by srlb on lines 3052 and 3054
- add length check for ISIS_SUBTLV_ALGORITHM
- fix conflict in fuzzing data during rebase

Signed-off-by: Igor Ryzhov <iryzhov@nfware.com>