Deprecated function: explode(): Passing null to parameter #2 ($string) of type string is deprecated in block_theme_suggestions_block()

Patch for the issue with same environment having php8.2 and drupal 10.2.3

Changes are made on on 11.x (our main development branch) first, and are then back ported as needed according to our policies.

I've just hit this on a client site too. Attempting to track down if it's something we should actually fix here or if its a problem with custom code.