[PLT-7793] Add /users/tokens/search endpoint (#8088)

* Add /users/tokens/search endpoint + tests

* Fix check-style

* Unnecessary deletion

model/user_access_token_search_test.go

@@ -0,0 +1,19 @@
+// Copyright (c) 2016-present Mattermost, Inc. All Rights Reserved.
+// See License.txt for license information.
+
+package model
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestUserAccessTokenSearchJson(t *testing.T) {
+	userAccessTokenSearch := UserAccessTokenSearch{Term: NewId()}
+	json := userAccessTokenSearch.ToJson()
+	ruserAccessTokenSearch := UserAccessTokenSearchFromJson(strings.NewReader(json))
+
+	if userAccessTokenSearch.Term != ruserAccessTokenSearch.Term {
+		t.Fatal("Terms do not match")
+	}
+}