Updated help text for team list for Mattermost slash commands

app/views/projects/mattermosts/_team_selection.html.haml

@@ -13,9 +13,9 @@
   = f.hidden_field(:team_id, value: selected_id, required: true) if @teams.one?
   .form-text.text-muted
     - if @teams.one?
-      This is the only available team.
+      This is the only available team that you are a member of.
     - else
-      The list shows all available teams.
+      The list shows all available teams that you are a member of.
     To create a team,
     = link_to "#{Gitlab.config.mattermost.host}/create_team" do
       use Mattermost's interface

changelogs/unreleased/mattermost-api-v4.yml

 ---
-title: Updated Mattermost integration to use API v4
+title: Updated Mattermost integration to use API v4 and only allow creation of Mattermost slash commands in the current user's teams
 merge_request: 19043
 author: Harrison Healey
 type: changed

spec/features/projects/services/user_activates_mattermost_slash_command_spec.rb

@@ -64,7 +64,7 @@ feature 'Setup Mattermost slash commands', :js do
       click_link 'Add to Mattermost'
 
       expect(page).to have_content('The team where the slash commands will be used in')
-      expect(page).to have_content('This is the only available team.')
+      expect(page).to have_content('This is the only available team that you are a member of.')
     end
 
     it 'shows a disabled prefilled select if user is a member of 1 team' do
@@ -94,7 +94,7 @@ feature 'Setup Mattermost slash commands', :js do
       click_link 'Add to Mattermost'
 
       expect(page).to have_content('Select the team where the slash commands will be used in')
-      expect(page).to have_content('The list shows all available teams.')
+      expect(page).to have_content('The list shows all available teams that you are a member of.')
     end
 
     it 'shows a select with team options user is a member of multiple teams' do