How to Generate .AAB file and Sign Android app Bundle using azure pipeline

I want to generate an Android app bundle(.aab) file using the Azure pipeline and facing an issue while generating the Android App Bundle file.

I have used the below Gradle task to generate and sign the .aab file. but, It generating the .APK file. I want to generate .aab file.

- task: Gradle@2
  inputs:
    gradleWrapperFile: 'gradlew'
    tasks: 'buildRelease'
    publishJUnitResults: false
    javaHomeOption: 'JDKVersion'
    sonarQubeRunAnalysis: false
    spotBugsAnalysis: false

Here is the script, Where I use jarsigner to sign the .aab file:

- task: CmdLine@2
  displayName: 'Signing and aligning AAB file(s) app\build\outputs\bundle\release\app-release.aab'
  inputs:
    script: 'jarsigner -verbose -sigalg SHA256withRSA -digestalg SHA-256 -keystore $(KeyStoreFile.secureFilePath) -storepass $(StorePassword) -keypass $(KeyPassword) $(system.defaultworkingdirectory)/app/build/outputs/bundle/release/app-release.aab $(KeyStoreAlias)'

In the Gradle tasks: I needed to change the tasks value 'buildRelease' to ':app:bundleRelease' to generate the .aab file.

Here is the .yaml file which I used to generate and sign .aab file:

trigger:
- master

pool:
  vmImage: ubuntu-latest

steps:
- task: DownloadSecureFile@1
  name: KeyStoreFile
  inputs:
    secureFile: 'AndroidApp.jks'

- task: Gradle@2
  inputs:
    gradleWrapperFile: 'gradlew'
    tasks: ':app:bundleRelease'
    publishJUnitResults: false
    javaHomeOption: 'JDKVersion'
    sonarQubeRunAnalysis: false
    spotBugsAnalysis: false


- task: CmdLine@2
  displayName: 'Signing and aligning AAB file(s) app\build\outputs\bundle\release\app-release.aab'
  inputs:
    script: 'jarsigner -verbose -sigalg SHA256withRSA -digestalg SHA-256 -keystore $(KeyStoreFile.secureFilePath) -storepass $(StorePassword) -keypass $(KeyPassword) $(system.defaultworkingdirectory)/app/build/outputs/bundle/release/app-release.aab $(KeyStoreAlias)'

- task: CopyFiles@2
  inputs:
    SourceFolder: '$(system.defaultworkingdirectory)/app/build/outputs/bundle/release/'
    Contents: '**'
    TargetFolder: '$(build.artifactstagingdirectory)'

- task: PublishBuildArtifacts@1
  inputs:
    PathtoPublish: '$(Build.ArtifactStagingDirectory)'
    ArtifactName: 'drop'
    publishLocation: 'Container'

There is below variables that I created and used in the signing task:

KeyStoreFile.secureFilePath
StorePassword
KeyPassword
KeyStoreAlias