* MM-62378: Initialize status and session cache before loading license
ps.LoadLicense could end up calling InvalidateAllCaches. Therefore,
we need to intialize those caches before calling LoadLicense
to prevent a panic from happening.
While here, we also remove some unused code.
https://mattermost.atlassian.net/browse/MM-62378
```release-note
NONE
```
* fix lint errors
```release-note
NONE
```
* fix test
```release-note
NONE
```