MM-60387: Bump Go version to 1.22 (#28118)

https://mattermost.atlassian.net/browse/MM-60387
```release-note
updated Go version to 1.22
```
---------

Co-authored-by: Mattermost Build <build@mattermost.com>

server/.go-version

@@ -1 +1 @@
-1.21.8
+1.22.6