🐛 [All Kits] Kit Params are not specifying when they require a non-empty value.

### [REQUIRED] Step 2: Describe your configuration

- Kit name: All of them, though I first saw this in `delete-user-data`
- Extension version: latest
- Configuration values (redact info where appropriate): n/a

### [REQUIRED] Step 3: Describe the problem

#### Steps to reproduce:

1. firebase functions:kits:install --package @next
2. Get to the point where you're configuring the kit params
3. Hit enter without entering text for them

##### Expected result

When you hit a param that _must_ have a value the CLI should force you to enter something (even if only a space, if you want more than that need regex validator)

##### Actual result

You can add a ton of empty params.

##### Analysis:

https://github.com/firebase/extensions/blob/kits/kits/delete-user-data/src/config.ts -- these are missing use of `input: { text: { nonEmpty: true } }` even when a param probably should require some value like FIRESTORE_PATHS.

We should broadly add `nonEmpty: true` across kits where required.