Steps to reproduce
Open Kibana and navigate to the "Machine Learning" section then tab through the buttons, the Screen Reader should announce the label associated with each button. In the case of the highlighted button in the screenshot, the Screen Reader only announces "Button", this occurs in multiple locations within the "Machine Learning" pages.

Screen Shot:

Expected Result
Screen Reader should announce "Button expand Nodes" or "Button collapse Nodes" or other text as appropriate

Kibana Version:
Kibana-8.13.2

OS:
Windows

Screen Reader:
NVDA ver 2024.3

Browser:
Chrome

Relevant WCAG Criteria:
WCAG Criterion - 4.1.2 Name, Role, Value - Level A
Buttons must have discernible text