[meteor] EJSONableCustomType shloud have clone and equal method optional

[uiii]

According to meteor docs a custom type registered to EJSON is allowed to omit the clone and equals methods. See https://docs.meteor.com/api/ejson.html#EJSON-addType

Please fill in this template.

• Use a meaningful title for the pull request. Include the name of the package modified.
• Test the change in your own code. (Compile and run.)
• Follow the advice from the readme.
• Avoid common mistakes.
• Run npm run lint package-name (or tsc if no tslint.json is present).

Select one of these and delete the others:

If changing an existing definition:

• Provide a URL to documentation or source code which provides context for the suggested changes: https://docs.meteor.com/api/ejson.html#EJSON-addType
• Increase the version number in the header if appropriate.
• If you are making substantial changes, consider adding a tslint.json containing { "extends": "dtslint/dt.json" }.

[dt-bot]

types/meteor/ejson.d.ts

to authors (@barbatus @fullflavedave @orefalo @dagatsoin @birkskyum @ardatan @stefanholzapfel). Could you review this PR?
👍 or 👎?

[ardatan]

👍 lgtm

[typescript-bot]

Approved by a listed owner. PR ready to merge pending express review by a maintainer.