htmlspecialchars() expects parameter 1 to be string, array given

Attached patch against Drupal 10.1.x

Re-rolled patch #2, for 9.5.x. Patch #2 no longer applies to 9.5.x. Not attaching interdiff as no patch is applying to 9.5

Would be really helpful if we can have testing steps in the description. Couple of suggestions after code review:

1. we can make use of isset instead of array_key_exists since its faster

if (is_array($text) && isset($text['#markup'])) {

2. The following comment needs to be better worded

// Handle strings that are passed in array as value in the #markup key.

I applied the suggestions please review.

The issue summary should be updated to include the problem, proposed solution, and remaining tasks

Title also should be updated to show the problem not the ticket number.

Also needs test coverage.

Ups, sorry.