Fail to create a container app with the default Express image name

OS: All
Build Version: 20230329.6

Repro Steps:

1. Open an Express project in VS Code which includes Dockerfile in it.
2. Right click one container app environment -> Select "Create Container App... -> Enter a container app name -> "Select "Build from project remotely using Azure Container Registry" -> Select an Azure Container Registry -> Select the default "Dockerfile" in the project folder -> Use the default express image name and fill the following steps to create a container app.
   
3. Check whether succeeds to create a container app or not.

Expect:
Succeed to create a container app with the default image name.

Actual:
Fail to create a container app with the default image name.

More Info:

1. This issue does not reproduce when creating container app with the default MVC/Django image name.
2. Succeed to create a container app with the name "myExpress or myExpress:latest".

Start by reproducing the container app creation flow with the default Dockerfile and Express image name, then trace where that default is handled in the VS Code extension. Done means the default Express image name creates the container app successfully, while the existing MVC and Django flows remain unaffected.