Also updating schema and specs.

Add model validation for max_issue_count

Add license check for max_issue_count

Add spec to check license handling

Move validation of max_issue_count and add creation list params

Move validation of max_issue_count

Add MR to changelog

Remove unnecessary comment

Remove unnecessary allow_null: false

Move changelog entry

Remove possible null value for max_issue_count from schema
definitions

Add max_issue_count response to documentation

Make methods private

Add condition to check max_issue_count was not changed in that situation

Replace stub_feature_flags with stub_licensed_features

Apply suggestion to ee/spec/controllers/boards/lists_controller_spec.rb
Add license check

Remove some new lines

Call super even if max issue count should be updated

Revert "Call super even if max issue count should be updated"

This reverts commit 7156ffa1464e69528757c06902db321f0cc28122.

Remove unnecessary validation

Move can_admin?(list) one level up

Apply new base request behavior

update of multiple fields is possible now
Add specs for create_list_attributes

Remove list_properties override

Add specs for UpdateService

Fix rubocop issue

Made execute_by_params private

Use parent to check for licensed feature

Use board_parent to check for available feature

Change order of checks

Move check into update method

Specs are now calling UpdateService

instead of just testing the module behavior

Use list board parent to check for feature availability

Add specs for conditional expose of max_issue_count

Use board parent licensed feature check

Apply pleitzens suggestion

Replace each / expect with all? / none? (rubocop)

Check result of service.execute

Apply suggested spec changes

Apply suggested changes to specs

Add check for empty response