v8.0 module release (#22975)

https://mattermost.atlassian.net/browse/MM-52079

```release-note
We upgrade the module version to 8.0. The new module path is github.com/mattermost-server/server/v8.
```


Co-authored-by: Doug Lauder <wiggin77@warpmail.net>

server/model/access_test.go

@@ -0,0 +1,55 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package model
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestAccessIsValid(t *testing.T) {
+	ad := AccessData{}
+
+	require.NotNil(t, ad.IsValid())
+
+	ad.ClientId = NewRandomString(28)
+	require.NotNil(t, ad.IsValid())
+
+	ad.ClientId = ""
+	require.NotNil(t, ad.IsValid())
+
+	ad.ClientId = NewId()
+	require.NotNil(t, ad.IsValid())
+
+	ad.UserId = NewRandomString(28)
+	require.NotNil(t, ad.IsValid())
+
+	ad.UserId = ""
+	require.NotNil(t, ad.IsValid())
+
+	ad.UserId = NewId()
+	require.NotNil(t, ad.IsValid())
+
+	ad.Token = NewRandomString(22)
+	require.NotNil(t, ad.IsValid())
+
+	ad.Token = NewId()
+	require.NotNil(t, ad.IsValid())
+
+	ad.RefreshToken = NewRandomString(28)
+	require.NotNil(t, ad.IsValid())
+
+	ad.RefreshToken = NewId()
+	require.NotNil(t, ad.IsValid())
+
+	ad.RedirectUri = ""
+	require.NotNil(t, ad.IsValid())
+
+	ad.RedirectUri = NewRandomString(28)
+	require.NotNil(t, ad.IsValid())
+
+	ad.RedirectUri = "http://example.com"
+	require.Nil(t, ad.IsValid())
+}