Revert "[MM-41576] Revamp database schema version (#19586)" (#19746)

* Revert "[MM-41576] Revamp database schema version (#19586)"

This reverts commit 645fee3fe3.

* Revert "MM-42049 - license endpoint not working (#19686)"

This reverts commit 4fe89e5847.

model/system.go

@@ -173,8 +173,3 @@ type WarnMetricStatus struct {
 type SendWarnMetricAck struct {
 	ForceAck bool `json:"forceAck"`
 }
-
-type AppliedMigration struct {
-	Version int    `json:"version"`
-	Name    string `json:"name"`
-}