Undefined array key warnings

[nlemoine]

Describe the bug

Various warnings related to undefined array (ACFE custom) keys because of weak checks like:

if($field['acfe_group_modal']) {
}

To Reproduce

Field groups registered before ACF extended installation.

Expected behavior

No warnings, make sure the keys exist.

Screenshots

WordPress & ACF
WordPress version: 6.7
ACF Pro version: 6.3.11
ACF add-ons: none