[CP-beta]Remove release_build: "false" which is interpreted as true due to a recipes bug. (flutter#168147)

This pull request is created by [automatic cherry pick workflow](https://github.com/flutter/flutter/blob/main/docs/releases/Flutter-Cherrypick-Process.md#automatically-creates-a-cherry-pick-request)
Please fill in the form below, and a flutter domain expert will evaluate this cherry pick request.

### Issue Link:
What is the link to the issue this cherry-pick is addressing?

flutter#168098

### Changelog Description:
Explain this cherry pick in one line that is accessible to most Flutter developers. See [best practices](https://github.com/flutter/flutter/blob/main/docs/releases/Hotfix-Documentation-Best-Practices.md) for examples

N/A

### Impact Description:
What is the impact (ex. visual jank on Samsung phones, app crash, cannot ship an iOS app)? Does it impact development (ex. flutter doctor crashes when Android Studio is installed), or the shipping production app (the app crashes on launch)

Works around infrastructure bug that would cause the release build process for release candidates to take longer than expected.

### Workaround:
Is there a workaround for this issue?

Yes, wait longer.

### Risk:
What is the risk level of this cherry-pick?

### Test Coverage:
Are you confident that your fix is well-tested by automated tests?

### Validation Steps:
What are the steps to validate that this fix works?

Already validated on master.

Author: flutteractionsbot

engine/src/flutter/.ci.yaml

@@ -308,7 +308,6 @@ targets:
     backfill: false
     properties:
       config_name: linux_android_aot_engine_ddm
-      release_build: "false"
     # Do not remove(https://github.com/flutter/flutter/issues/144644)
     # Scheduler will fail to get the platform
     drone_dimensions:
@@ -345,7 +344,6 @@ targets:
     timeout: 120
     backfill: false
     properties:
-      release_build: "false"
       config_name: linux_android_debug_engine_ddm
     # Do not remove(https://github.com/flutter/flutter/issues/144644)
     # Scheduler will fail to get the platform