Views text area plugin does not declare a dependency on the text format it uses

I converted the patch in #2 to an MR. Then I fixed it because the return value from calculateDependencies() was incorrect. I added a test. At some point I realized that this needed an update path. So I wrote that and added a test for it too.

I did not address the question in #13. I wasn't sure if it's necessary since plugins are @internal.

Change applies cleanly, test pass and the correct dependency is now added to the exported config. I think this is OK to go.

Probably need to update any default views that ship with core to include these. Example views.view.frontpage.yml in node, there may be others.

Results of grep -rn "plugin_id: text$" --include views.view.*.yml:

core/profiles/demo_umami/config/install/views.view.frontpage.yml:303:          plugin_id: text
core/profiles/demo_umami/config/install/views.view.frontpage.yml:373:          plugin_id: text
core/modules/content_translation/tests/modules/content_translation_test_views/test_views/views.view.test_entity_translations_link.yml:104:          plugin_id: text
core/modules/views/tests/fixtures/update/views.view.test_filter_format_dependencies.yml:164:          plugin_id: text
core/modules/views/tests/fixtures/update/views.view.test_entity_id_argument_update.yml:193:          plugin_id: text
core/modules/views/tests/modules/views_test_config/test_views/views.view.test_display_empty.yml:34:          plugin_id: text
core/modules/views/tests/modules/views_test_config/test_views/views.view.test_display_empty.yml:40:          plugin_id: text
core/modules/views/tests/modules/views_test_config/test_views/views.view.test_entity_id_argument.yml:160:          plugin_id: text
core/modules/views/tests/modules/views_test_config/test_views/views.view.test_tokens.yml:109:          plugin_id: text
core/modules/views/tests/modules/views_test_config/test_views/views.view.test_tokens.yml:141:          plugin_id: text
core/modules/views/tests/modules/views_test_config/test_views/views.view.test_destroy.yml:50:          plugin_id: text
core/modules/views/tests/modules/views_test_config/test_views/views.view.test_destroy.yml:56:          plugin_id: text
core/modules/views/tests/modules/views_test_config/test_views/views.view.test_destroy.yml:148:          plugin_id: text
core/modules/views/tests/modules/views_test_config/test_views/views.view.test_destroy.yml:154:          plugin_id: text
core/modules/views/tests/modules/views_test_config/test_views/views.view.test_destroy.yml:161:          plugin_id: text
core/modules/views/tests/modules/views_test_config/test_views/views.view.test_destroy.yml:167:          plugin_id: text
core/modules/views/tests/modules/views_test_config/test_views/views.view.test_token_view.yml:205:          plugin_id: text
core/modules/views_ui/tests/modules/views_ui_test/config/install/views.view.sa_contrib_2013_035.yml:178:          plugin_id: text

Not all of those views specified the content of the text, so there was nothing to update in those cases. But I updated the ones that needed a dependency.