Support enum dropdown for configuration arrays in settings UI

[letmaik]

     "myext.option": {
          "type": "array",
          "items": {
            "type": "string",
            "enum": [
              "A",
              "B"
            ]
          }
      }

Currently (1.38), the settings UI only shows an enum dropdown when the setting is not an array. In the example above only an "Add Item" button is shown with free-text input. A dropdown would be better.

[vscodebot]

(Experimental duplicate detection)
Thanks for submitting this issue. Please also check if it is already covered by an existing one, like:

• Support "uniqueItems" in configuration UI (#80536)

[letmaik]

@chrmarti The vscodebot shouldn't suggest duplicate issues if they are from the same author (myself). It's quite unlikely that this would happen.

[chrmarti]

@letmaik Good point, adding it to the bot's issues. Thanks.

[octref]

Duplicate of #77458.