androidenv/emulate-app: fix image id for recent device manager

Symptom:
```
Available Android targets:
----------
id: 1 or "android-28"
     Name: Android 9
     Type: Platform
     API level: 28
     Revision: 6
     Skins: HVGA, QVGA, WQVGA400, WQVGA432, WSVGA, WVGA800 (default), WVGA854, WXGA720, WXGA800, WXGA800-7in
 Tag/ABIs : google_ndk_playstore/x86
...
Error: Invalid --tag google_apis_playstore for the selected target.
```

For creation of AVD, switch from `android` to `avdmanager` as the
latter seems enabling selecting the image with less friction (and is
better documented as not deprecated).  This requires using recent
tools - from https://developer.android.com/studio/releases/sdk-tools :
> SDK Tools, Revision 25.3.0 (March 2017)
> ...
> `android avd` command-line functionality replaced with new
> `avdmanager` tool.

For listing of targets, switch from `android` to `avdmanager` as the
`android` command invocation fails in recent tools.  Symptom (not
missing `s` as backward incompatibility):
```
Invalid or unsupported command "list targets"

Supported commands are:
android list target
android list avd
android list device
android create avd
android move avd
android delete avd
android list sdk
android update sdk
```

References:
- https://developer.android.com/studio/tools/help/android
- https://developer.android.com/studio/command-line/avdmanager