schema: Allow verbose no-argument actions in the settings schema

[Weichenleeeee123]

Summary of the Pull Request

• Adds a strict schema definition for verbose forms of actions that take no arguments.
• Wires four existing optional-argument action schemas into FullCommand.command.
• Preserves required-argument validation and rejects unexpected arguments for no-argument actions.

References and Relevant Issues

Closes #11332

Detailed Description of the Pull Request / Additional comments

Windows Terminal accepts both of these forms:

{ "command": "toggleAlwaysOnTop" }
{ "command": { "action": "toggleAlwaysOnTop" } }

The settings schema only accepted the short form because FullCommand.command
had no object branch for actions without arguments.

This adds a strict NoArgsAction definition for the 39 argument-free actions.
It also connects the existing AddMarkAction, SetFocusModeAction,
SetFullScreenAction, and SetMaximizedAction definitions, which were not
referenced by FullCommand.command.

Validation Steps Performed

Validated doc/cascadia/profiles.schema.json with PowerShell 7.6 Test-Json:

• All 39 no-argument actions validate in verbose form.
• Existing short forms still validate.
• Empty and populated forms of the four optional-argument actions validate.
• Actions missing required arguments remain invalid.
• Unknown actions, incorrect argument types, and unexpected arguments remain invalid.
• The schema parses successfully and git diff --check passes.

PR Checklist

• Closes Schema does not allow actions without arguments in verbose form #11332
• Tests added/passed
• Documentation updated
• Schema updated (if necessary)