[base-controller] Implement utility function registerActionHandlers for batch registering all internal actions of a controller class

[MajorLift]

Motivation

• Currently, we manually enumerate each individual registerActionHandler call in controller constructors (example). We should have a DRY-er way of doing this.
• Most handlers for controller internal actions are simply public controller class methods bound to the controller instance.

Proof of concept

  // TODO: Expand into base-controller utility function that batch registers action handlers.
  #registerActionHandlers() {
    const methodsExcludedFromMessenger = [
      'constructor',
      'messagingSystem',
      'setProvider',
      'provider',
      'ipfsGateway',
      'chainId',
    ];

    getKnownPropertyNames<keyof this>(Object.getPrototypeOf(this)).forEach(
      (method) => {
        if (
          ((key: keyof this): key is AssetsContractControllerMethodName =>
            !methodsExcludedFromMessenger.find((e) => e === key) &&
            typeof this[key] === 'function')(method)
        ) {
          this.messagingSystem.registerActionHandler(
            `${name}:${method}`,
            // TODO: Write a generic for-loop implementation that iterates over an input union type in tandem with the input array.
            // @ts-expect-error Both assigned argument and assignee parameter are using the entire union type for `method` instead of the type for the current element
            this[method].bind(this),
          );
        }
      },
    );
  }

https://github.com/MetaMask/core/pull/4397/files#diff-7ada7b099f6bcc6f3d4acd71f94b604636abd22cc556a76dbe7b3e610b1d9233R235-R262

Acceptance Criteria

• MVP: Write a function that...
  • a) Accepts a list of public controller class fields and methods that should be excluded from being registered as action handlers.
    • constructor and messagingSystem should be included by default.
  • b) Iterates over a list of public controller methods, and binds them to the controller instance.
  • c) Registers these bound methods as action handlers for the corresponding internal messenger actions.
    • This iteration is correctly typed.
• Stretch: Better handling for exceptions.
  • a) Accepts a map of action names and handlers which are exceptions to the general rule that each class method corresponds to an action handler.
  • b) Register these exceptions to the messagingSystem as well.