fix(android/engine): Handle parsing empty JSONArray as JSONObject

Co-authored-by: Marc Durdin <marc@durdin.net>

feat(web): Custom layer targets for Shift double-tap

fix(common): always define dry_run variable

fix(android/app): Add check if bundle to PackageActivity is null

Applies proposed feature https://community.software.sil.org/t/testing-caps-on-touch/6849/5:

1. A `caps` layer must still exist in the keyboard.
2. If there is at least one multitap subkey defined on the Shift key on
   the active layer, then the `nextlayer` property of the first multitap
   subkey for the Shift key will be used instead of the default `caps`.
3. This does not change the behavior of the Shift key otherwise.

For example, the following defines a valid multitap key on Shift on the
`rightalt` layer to switch to a custom extended `rightalt-shift-caps`
layer.

This does not implement any other multitap functionality. It just allows
the keyboard developer to specify a target layer for a given double-tap.

```
  {
    "id": "K_SHIFT",
    "text": "*Shift*",
    "width": 150,
    "sp": 1,
    "nextlayer": "rightalt-shift",
    "layer": "default",
    "multitap": [
      {
        "text": "",
        "id": "T_new_694",
        "sp": "1",
        "nextlayer": "rightalt-shift-caps"
      }
    ]
  },
```

fix(developer): handle high-bit-set HKL correctly

fix(developer): support gif preview images in Package Editor

fix(developer): Make Details and Build tabs scrollable

Fixes #7599.

MSKLC HKLs have high bit set, which means that we need to explicitly
cast from Integer to DWord to avoid range check errors.

auto: increment beta version to 16.0.96

fix(developer): publish `@keymanapp/keyman-version` to npm