feat(dom): toBePressed and toBePartiallyPressed

[KeylaMunnoz]

What has been added:

• toBePressed and toBePartiallyPressed assertions
• isButtonElement and isValidAriaPressed helpers
• tests for these assertions

[JDOM10]

Hey @KeylaMunnoz! Thank you for working on this, this is looking great! Just left a small comment

Anything else you would like to add? @suany0805

[suany0805]

Nice Work! just left a couple of comments

[suany0805]

maybe rename to pressedAttributeValue, since I get you could receive: true, false or mixed.

[suany0805]

can you explain what does mixed specifically involve ? (for context and understanding)

[KeylaMunnoz]

Hey Su sure ! mixed represents a partially pressed state so it's typically used when a toggle button controls multiple items and only some of them are in the pressed state.
In these cases, the button cannot be accurately described as either fully pressed (true) or not pressed (false), so mixed indicates that the controlled state is not consistent across the affected items.

[suany0805]

Nice work! just left small comments, please address them before merging