fix(ashby): remove filterCandidateId from removed-subblock migrations

The candidate-id filter was reintroduced as a valid Ashby subBlock, but
the migration map still rewrote it to _removed_filterCandidateId on every
workflow load, silently breaking the field. Drop the entry so user values
persist.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Author: waleedlatif1

apps/sim/lib/workflows/migrations/subblock-migrations.ts

@@ -34,7 +34,6 @@ export const SUBBLOCK_ID_MIGRATIONS: Record<string, Record<string, string>> = {
   ashby: {
     emailType: '_removed_emailType',
     phoneType: '_removed_phoneType',
-    filterCandidateId: '_removed_filterCandidateId',
     expandApplicationFormDefinition: '_removed_expandApplicationFormDefinition',
     expandSurveyFormDefinitions: '_removed_expandSurveyFormDefinitions',
   },