Fix auto-complete in slash command for shared channel invite (#25524)

* fix auto-complete in slash command for shared channel invite

* more providers not implementing AutocompleteDynamicArgProvider

---------

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

server/channels/app/slashcommands/command_share.go

@@ -17,6 +17,9 @@ import (
 type ShareProvider struct {
 }
 
+// ensure ShareProvide implements AutocompleteDynamicArgProvider
+var _ app.AutocompleteDynamicArgProvider = (*ShareProvider)(nil)
+
 const (
 	CommandTriggerShare   = "share-channel"
 	AvailableShareActions = "invite, uninvite, unshare, status"