fix: install platform before plugin so platform-specific preferences are included

[peitschie]

Platforms affected

All platforms.

Motivation and Context

If the plugin is installed before the platform, cordova will not populate the default preference values specified by the plugin. In cases where the preference is a mandatory value, this can cause the plugin to fail to build.

Description

Re-ordered the setup commands so it's now platform, then plugin etc.

Testing

I've ensured that a plugin with default preferences (e.g., https://github.com/don/cordova-plugin-ble-central) has these preferences appear in the generated config.xml and package.json files in the test app that cordova-paramedic generates.

Checklist

• I've run the tests to see all new and existing tests pass
• I added automated test coverage as appropriate for this change
• Commit is prefixed with (platform) if this change only applies to one platform (e.g. (android))
• If this Pull Request resolves an issue, I linked to the issue in the text above (and used the correct keyword to close issues using keywords)
• I've updated the documentation if necessary