Workflow inputs to dynamically deploy to channel

### The use case you're trying to solve

I'm building a a workflow where maintainer can select the channel they want the app is published into. For example, `live`, `staging` (long-lived preview), and `‎` (new preview)


```yaml
name: Deploy to Firebase Hosting
"on":
workflow_dispatch:
inputs:
deployChannel:
description: "Channel which Firebase will deploy into"
default: ""
type: choice
options:
- live
- staging
-

... some actions

- name: Deploy to Firebase Hosting
uses: FirebaseExtended/action-hosting-deploy@v0
id: firebaseHost
with:
repoToken: "${{ secrets.GITHUB_TOKEN }}"
firebaseServiceAccount: "${{ secrets.SOME_SECRETS }}"
channelId: ${{ inputs.deployChannel }} # value from the input above
projectId: someprojectid
```

If I understand from the docs, the deploy to a new preview channel, just leave the `channelId` property empty. I tried to achive that by passing an empty value.

However, on clicking **Run workflow**. GitHub immediately crashed, seems like it didn't support empty value?


No files or tests are named. Start by reproducing the workflow_dispatch form with an empty choice and trace how deployChannel reaches the Firebase Hosting deploy action; done means selecting the empty option no longer crashes Run workflow and deploys to a new preview channel.

Written by the indexing model from the issue text.