Create plugin for altering ArgumentDefinitions in UI

Problem/Motivation

With the ability to create tools in the UI based on tools in code, we want to enable users to refine and restrict parts of a base tool for more focused use cases. One example would be the ability to create a tool based on the 'send_email' tool, with the recipient value preset, or to limit the recipient to a small list of email addresses.

Proposed resolution

Create a 'Alter Argument Definition' plugin of type ArgumentDefinitionModifier, that exposes values from the source definition to be changed. We need to be mindful of what can and can't be changed:

• (immutable) @param string $data_type
• (mutable)@param string|null|\Stringable $label
• (immutable*)@param bool $required (if required made optional, default value will need to be required)
• (immutable) @param bool $multiple
• (mutable)@param string|null $description
• (mutable)@param mixed $default_value
• (mutable)@param array $constraints
• (immutable)@param bool $locked
• (mutable)@param array $form_alter
• (mutable)@param array $config_schema_override

A constraints UI likely creates the most complexity here.

Remaining tasks

User interface changes

API changes

Data model changes