Fix dependencies of taxonomy term translation migrations

The first step was to add a skip_on_empty if the content language settings existed.

So, that proves that the new pipeline works.

Then add an optional dependency on d7_entity_translation_settings d7_language_content_taxonomy_vocabulary_settings.yml so that it runs first. And then add a dependency on d7_language_content_taxonomy_vocabulary_settings to the taxonomy term translation migrations.

The changes to drupalci and the test are not needed, that leaves a patch with changes to 4 migrations.

Edit: s/to a 4/to 4/

I triaged this RTBC issue sometime in the last weeks but didn't leave a comment.

I didn't find anything that needed to be done.

Leaving at RTBC

The patch in #4 was failing and I tracked it to #3015369: Fix MigrateTestBase::executeMigrations() to execute migrations in dependency order. That issue ensures that the migrations will be ordered by dependency before execution. This resulted in the following error.

1) Drupal\Tests\node\Kernel\Migrate\d7\MigrateNodeTest::testNode
'language_content_settings' entity with ID 'node.et' already exists. (/var/www/html/core/lib/Drupal/Core/Entity/EntityStorageBase.php:519)
Failed asserting that two strings are equal.

This is happening because 'language_content_settings' was being run last in that group. It needs to be before any translation migration and other 'language_content_settings' ones. The change was to add a dependency to d7_language_content_taxonomy_vocabulary_settings.yml so that it runs after d7_language_content_settings, if it exists.