Caching empty containers in the Velocity2 cache when accessing in a language where the content doesn't exist

[swicken-dotcms]

Describe the bug
If you access a page in a language where the page and the content in the page both do not exist we are caching the empty container in the Velocity2 cache

Reproduced on: 21.06, 22.06

Related Ticket: https://dotcms.zendesk.com/agent/tickets/107703

To Reproduce
The environment must be configured with the defaults for the two following variables:

DEFAULT_CONTENT_TO_DEFAULT_LANGUAGE=false
DEFAULT_PAGE_TO_DEFAULT_LANGUAGE=true

1. From the demo starter, create a page called 'test-page' in the root in English
2. Add a new Rich Text contentlet to the container on that page in English
   NOTE: Do not add Spanish versions of either the page or the content
3. Clear the cache
4. In another browser/incognito, go to http://localhost:8080/test-page?language_id=2, you will correctly see an empty container
5. Now go to http://localhost:8080/test-page?language_id=1 and you will incorrectly see an empty container
6. Clear the Velocity2 cache and revisit http://localhost:8080/test-page?language_id=1, the Rich Text will properly display

It appears we are caching the alternate language versions of content into the fallback default page containers in the Velocity2 cache

Expected behavior
When falling back we should not cache the content into the default language container

Additional context
This only occurs when we fall back the page and not the content. If the page exists in both languages but the content does not, it is cached correctly.
It als only occurs if the non-existent language is accessed before the default, otherwise the default language gets properly cached.

WORKAROUNDS
Create a version of the page in all languages
Set DEFAULT_CONTENT_TO_DEFAULT_LANGUAGE to true

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[jcastro-dotcms]

INTERNAL QA: PASSED

After following the STR provided by @swicken-dotcms , this is what is happening after the code fix:

• Going to http://localhost:8080/test-page?language_id=2 : The page displays an empty Container.
• Going to http://localhost:8080/test-page?language_id=1 : The page displays the expected test Contentlet now, without having to flush any cache regions.

[josemejias11]

Approved: Tested on master_7713bff_SNAPSHOT, Docker, macOS 13.0, FF v113.0