[MM-25652] Add /integrity endpoint to local mode API (#15033)

* Fix direct/group channel false positives

* Move public structures to model package

* Expose CheckIntegrity as a local API method

* Remove extra file

Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

store/sqlstore/supplier.go

@@ -1184,8 +1184,8 @@ func (ss *SqlSupplier) getQueryBuilder() sq.StatementBuilderType {
 	return builder
 }
 
-func (ss *SqlSupplier) CheckIntegrity() <-chan store.IntegrityCheckResult {
-	results := make(chan store.IntegrityCheckResult)
+func (ss *SqlSupplier) CheckIntegrity() <-chan model.IntegrityCheckResult {
+	results := make(chan model.IntegrityCheckResult)
 	go CheckRelationalIntegrity(ss, results)
 	return results
 }