add & to chars that must be treated as spaces (#23786)

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

server/channels/store/sqlstore/channel_store.go

@@ -3561,7 +3561,7 @@ func (s SqlChannelStore) buildLIKEClauseX(term string, searchColumns ...string)
 	return searchFields
 }
 
-const spaceFulltextSearchChars = "<>+-()~:*\"!@"
+const spaceFulltextSearchChars = "<>+-()~:*\"!@&"
 
 func (s SqlChannelStore) buildFulltextClause(term string, searchColumns string) (fulltextClause, fulltextTerm string) {
 	// Copy the terms as we will need to prepare them differently for each search type.