Enable Assessment Issue in assessment report json

[sanyamsinghal]

Describe the changes in this pull request

• also separated out the report struct for ybd payload
  Replacement of this change - Implement custom Json Marshaller for AssessmentReport struct #2205
  https://yugabyte.atlassian.net/browse/DB-14926

Describe if there are any user-facing changes

Yes, assessment json report will have new field AssessmentIssues, for now this is redudant since we have old fields also.
Once we verify and upate the existing tests then we can remove this field

How was this pull request tested?

Existing tests passing is enough

Does your PR have changes that can cause upgrade issues?

Component	Breaking changes?
MetaDB	Yes/No
Name registry json	Yes/No
Data File Descriptor Json	Yes/No
Export Snapshot Status Json	Yes/No
Import Data State	Yes/No
Export Status Json	Yes/No
Data .sql files of tables	Yes/No
Export and import data queue	Yes/No
Schema Dump	Yes/No
AssessmentDB	Yes/No
Sizing DB	Yes/No
Migration Assessment Report Json	Yes <--
Callhome Json	Yes/No
YugabyteD Tables	Yes/No
TargetDB Metadata Tables	Yes/No

[makalaaneesh]

LGTM with one comment.
Pls verify that yugabyted UI is not broken.