[23.0] Fix Webhooks not rendering

[ElectronicBlueberry]

The phdcomics webhook on galaxy eu failed to render. After investigating the issue, I discovered this was due to missing prototype functions in webhooks.js. These seem to have been provided by backbone.js in the past, but were currently missing from the objects. Unsure where these functions were meant to be injected, I removed the use of them instead. This fixed the rendering issue.

How to test the changes?

(Select all options that apply)

• I've included appropriate automated tests.
• This is a refactoring of components with existing test coverage.
• Instructions for manual testing are as follows:
  1. [add testing steps and prerequisites here if you didn't write automated tests covering all your changes]

License

• I agree to license these and all my past contributions to the core galaxy codebase under the MIT license.

[martenson]

Thanks @ElectronicBlueberry