Hide Build button for Flutter app or fail gracefully on click.

## Steps to Reproduce

I created a new Flutter project (this happens either if I create it in IntelliJ IDEA or in Android Studio) and selected to build it clicking here:


Then I get the following Error message:


Clicking OK opens this dialog:


The `` drop down menu have these options:


If I select one of the options and try to build again, I get another error:


Clicking OK opens the same dialog as before, and I think I am supposed to fill in something at the `Project compiler output` field:


What should I place there? Is this really necessary? Why isn't this being configured at project creation?

## Version info

[√] Flutter (Channel stable, v1.7.8+hotfix.3, on Microsoft Windows [Version 10.0.17763.557], locale pt-BR)
• Flutter version 1.7.8+hotfix.3 at C:\Programacao\Flutter\sdk\flutter
• Framework revision b712a172f9 (8 days ago), 2019-07-09 13:14:38 -0700
• Engine revision 54ad777fd2
• Dart version 2.4.0

[√] Android toolchain - develop for Android devices (Android SDK version 29.0.1)
• Android SDK at C:\Programacao\Android\Sdk
• Android NDK location not configured (optional; useful for native profiling support)
• Platform android-29, build-tools 29.0.1
• Java binary at: C:\Program Files\Android\Android Studio\jre\bin\java
• Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1343-b01)
• All Android licenses accepted.

[√] Android Studio (version 3.4)
• Android Studio at C:\Program Files\Android\Android Studio
• Flutter plugin version 37.0.1
• Dart plugin version 183.6270
• Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1343-b01)

[!] IntelliJ IDEA Ultimate Edition (version 2018.2)
• IntelliJ at C:\Program Files\JetBrains\IntelliJ IDEA 2018.1.5
X Flutter plugin not installed; this adds Flutter specific functionality.
X Dart plugin not installed; this adds Dart specific functionality.
• For information about installing plugins, see
https://flutter.dev/intellij-setup/#installing-the-plugins

[√] IntelliJ IDEA Ultimate Edition (version 2019.1)
• IntelliJ at C:\Program Files\JetBrains\IntelliJ IDEA 2019.1
• Flutter plugin version 37.1.3
• Dart plugin version 191.7830

[√] VS Code (version 1.35.1)
• VS Code at C:\Users\Michel Feinstein\AppData\Local\Programs\Microsoft VS Code
• Flutter extension version 2.25.1

[√] Connected device (1 available)
• ONEPLUS A5000 • bc18175a • android-arm64 • Android 9 (API 28)

! Doctor found issues in 1 category.
Process finished with exit code 0