Components: Deprecate outer margins

[mirka]

What problem does this address?

A lot of components currently have inherent outer margins, making it hard to reuse in different contexts since it requires a style override (often of an internal element). This kind of style override is something we want to discourage.

What is your proposed solution?

Deprecate the bottom margin (similar to #37160), following the guidelines stipulated in the devdocs.

Components

Each component first needs a __nextHasNoMarginBottom prop to opt in, and then they also need to be officially deprecated after all in-repo usage has been migrated.

• AnglePickerControl
  • prop added AnglePickerControl: Add flag to remove bottom margin #43160
  • deprecated AnglePickerControl: Deprecate margin bottom #43867
  • hard deprecated AnglePickerControl: Hard deprecate bottom margin #58700
• BaseControl
  • prop added BaseControl: Add opt-in prop for margin-free styles #39325
  • deprecated
  • Components built with BaseControl tracked in BaseControl: Deprecate bottom margin #38730
• CustomGradientPicker
  • prop added (Custom)GradientPicker: Add flag to remove margins #43387
  • deprecated (Custom)GradientPicker: Remove and deprecate outer margins #43436
  • hard deprecated CustomGradientPicker: Hard deprecate outer margins #58699
• DuotonePicker (when duotonePalette={ [] } and unsetable={ false })
  • fix as bug DuotonePicker: Fix top margin when no duotone options #57489
• FontSizePicker FontSizePicker: Deprecate bottom margin #38720
  • prop added FontSizePicker: Add flag to remove bottom margin #43062
  • deprecated FontSizePicker: Deprecate bottom margin #43870
  • hard deprecated FontSizePicker: Hard deprecate bottom margin #58702
• GradientPicker
  • prop added (Custom)GradientPicker: Add flag to remove margins #43387
  • deprecated (Custom)GradientPicker: Remove and deprecate outer margins #43436
  • hard deprecated GradientPicker: Hard deprecate outer margins #58701
• FormTokenField (encountered here)
  • prop added FormTokenField: Add prop to remove bottom margin #48609
  • deprecated
  • hard deprecated

Block Editor Components

• LineHeightControl: Enhance interactions by migrating internals to NumberControl on Style options. #37160
• URLInput: Deprecate bottom margin #46692

(Component lists may not be exhaustive, please add)