Fix color palette dropdown not closing on custom color selection

[iqbal-web]

What?

Fixed #74154

Why?

Selecting a custom color might prevent the color palette from closing.

How?

• Updated renderContent to receive and pass the onClose callback to ColorGradientControl
• Added onClose parameter to ColorGradientControlInner function
• Updated both color and gradient onChange handlers to call onClose?.() after setting the new value

Testing Instructions

Testing Instructions for Keyboard

Screenshots or screencast

Before	After

[github-actions]

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[github-actions]

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[SirLouen]

This seems to be a close candidate. It seems you are patching the problem, but not addressing the underlying issue.

I'm going to leave it open for now, but this might close in favor to #74179

cc @t-hamano

[SirLouen]

This is not going to happen. Closing.