In the Bicep file you can output variables:
output laPrincipalId string = logicAppResource.identity.principalId
So how do I then pass these to another Yaml task?
My first research found this perfect discussion: BICEP Output to Pipeline Variables #4638
So this is the task that populates the output variables as pipeline variables after the create resource task:
Then the output variable can be used like so:
parameters:
principalId: '$(bicepOutput.laPrincipalId)'