[MM-61765] Fix errcheck issues in server/channels/app/platform/license.go (#30954)

* [MM-61765] Fix errcheck issues in server/channels/app/platform/license.go

- Removed the errcheck exception for license.go from .golangci.yml
- Added proper error handling for RemoveLicense() calls
- Added proper error handling for ReloadConfig() and InvalidateAllCaches() calls
- Updated variable names to avoid conflicts

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

* simplify naming

---------

Co-authored-by: Claude <noreply@anthropic.com>

server/.golangci.yml

@@ -94,7 +94,6 @@ issues:
         channels/app/helper_test.go|\
         channels/app/permissions_test.go|\
         channels/app/platform/helper_test.go|\
-        channels/app/platform/license.go|\
         channels/store/localcachelayer/channel_layer.go|\
         channels/store/localcachelayer/channel_layer_test.go|\
         channels/store/localcachelayer/emoji_layer.go|\