Add read_channel_content permission (#24018)

* Add read_channel_content permission

* fix tests

* update system console default permissions per role

* add read_channel_content to e2e defaultRolesPermissions

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

server/channels/testlib/store.go

@@ -70,6 +70,7 @@ func GetMockStoreForSetupFunctions() *mocks.Store {
 	systemStore.On("GetByName", model.MigrationKeyAddCustomUserGroupsPermissions).Return(&model.System{Name: model.MigrationKeyAddCustomUserGroupsPermissions, Value: "true"}, nil)
 	systemStore.On("GetByName", model.MigrationKeyAddPlayboosksManageRolesPermissions).Return(&model.System{Name: model.MigrationKeyAddPlayboosksManageRolesPermissions, Value: "true"}, nil)
 	systemStore.On("GetByName", model.MigrationKeyAddCustomUserGroupsPermissionRestore).Return(&model.System{Name: model.MigrationKeyAddCustomUserGroupsPermissionRestore, Value: "true"}, nil)
+	systemStore.On("GetByName", model.MigrationKeyAddReadChannelContentPermissions).Return(&model.System{Name: model.MigrationKeyAddReadChannelContentPermissions, Value: "true"}, nil)
 	systemStore.On("GetByName", "CustomGroupAdminRoleCreationMigrationComplete").Return(&model.System{Name: model.MigrationKeyAddPlayboosksManageRolesPermissions, Value: "true"}, nil)
 	systemStore.On("GetByName", "products_boards").Return(&model.System{Name: "products_boards", Value: "true"}, nil)
 	systemStore.On("GetByName", "elasticsearch_fix_channel_index_migration").Return(&model.System{Name: "elasticsearch_fix_channel_index_migration", Value: "true"}, nil)