fix(schema-plugin):fix table ddl do not show unique index when table is partitioned

[PeachThinking]

What type of PR is this?

type-bug

What this PR does / why we need it:

fix table ddl do not show unique index when table is partitioned

Which issue(s) this PR fixes:

Fixes #2236

Special notes for your reviewer:

Additional documentation e.g., usage docs, etc.: