Hardcode security coverage EOL dates for Drupal 9.4 and 9.5 (as was done for 8.8 and 8.9)

Problem/Motivation

In #2991207: Drupal core should inform the user of the security coverage for the site's installed minor version including final 8.x LTS releases, we implemented messages for the site owner about the security coverage dates for their installed release. The implementation assumes each minor receives security coverage until two minors later. However, the last 1-2 minor versions of the major series need to have specific dates hardcoded, because there is no "two minors later".

Proposed resolution

Add the dates for 9.4.x and 9.5.x.

Adding appropriately named constants will automatically generate the correct messages (as shown in the test cases).

Remaining tasks

Needs code review.

Manual testing requires faking update module data, because the message is not displayed unless the branch has a stable release.

Alternately, manual testing with the below changes will display the message as if 9.2 and 9.3 were the final releases instead. (This works because Drupal.org already has stable releases for those branches.)

diff --git a/core/modules/update/src/ProjectSecurityData.php b/core/modules/update/src/ProjectSecurityData.php
index 6c927c5e0f..03e6cd3ab6 100644
--- a/core/modules/update/src/ProjectSecurityData.php
+++ b/core/modules/update/src/ProjectSecurityData.php
@@ -39,13 +39,13 @@ final class ProjectSecurityData {
    *
    * @see \Drupal\update\ProjectSecurityRequirement::getDateEndRequirement()
    */
-  const SECURITY_COVERAGE_END_DATE_9_4 = '2023-06-21';
+  const SECURITY_COVERAGE_END_DATE_9_2 = '2023-06-21';
 
-  const SECURITY_COVERAGE_ENDING_WARN_DATE_9_4 = '2022-12-14';
+  const SECURITY_COVERAGE_ENDING_WARN_DATE_9_2 = '2022-12-14';
 
-  const SECURITY_COVERAGE_END_DATE_9_5 = '2023-11';
+  const SECURITY_COVERAGE_END_DATE_9_3 = '2023-11';
 
-  const SECURITY_COVERAGE_ENDING_WARN_DATE_9_5 = '2023-05-14';
+  const SECURITY_COVERAGE_ENDING_WARN_DATE_9_3 = '2023-05-14';
 
   /**
    * The existing (currently installed) version of the project.

User interface changes

Drupal 9.4 and 9.5 will properly inform the user of accurate EOL dates.

API changes

• API addition of magically named class constants as added in response to #2991207-155: Drupal core should inform the user of the security coverage for the site's installed minor version including final 8.x LTS releases.
• Deprecation or removal of the D8 legacy dates.

Data model changes

None.

Release notes snippet

TBD