[Strict Mode] EuiResizeObserver doesn't work

[weronikaolejniczak]

Describe the bug

When Strict Mode is enabled, EuiResizeObserver doesn't work. Example usage in EuiAccordion - dynamic height changes don't work.

Docs page

Strict Mode	No Strict Mode

Impact and severity

It impacts all end-users of our consumers. Severe.

There is no known workaround.

[Search] EuiResizeObserver is used internally in:

• EuiRange (Kibana, 42)
• EuiToolTip (Kibana, 856)
• EuiAccordion (Kibana, 213)
• EuiContextMenu (Kibana, 335)
• EuiTextTruncate (Kibana, 12)
• EuiMarkdownEditor (Kibana, 10)

[Search] EuiResizeObserver is used in Kibana 16 times

Environment and versions

• EUI version: ~
• React version: React 18 (Strict Mode)
• Kibana version (if applicable): ~
• Browser: ~
• Operating System: ~

Minimum reproducible sandbox

Codesandbox

To Reproduce

1. Enable Strict Mode in your environment.
2. Render EuiResizeObserver.
3. Notice that it doesn't react to resizes and returned values don't change.

Expected behavior

EuiResizeObserver reacts to dimension changes and returns correct values.