"az containerapp env telemetry app-insights set" fails to set connection string

### Describe the bug

Executing the az containerapp env telemetry app-insights set command as per the documentation results in the response:

{
"connectionString": null,
"enableOpenTelemetryLogs": true,
"enableOpenTelemetryTraces": true
}

with the connection string not being set and no indication of the reason.

### Related command

az containerapp env telemetry app-insights set -n env-album-containerapps -g album-containerapps --connection-string "" --enable-open-telemetry-traces true --enable-open-telemetry-logs true

### Errors

No error message is generated - the command doesn't work as expected.

### Issue script & Debug output

Editing the debug output for privacy is non-trivial; please provide a method to produce debug output with sensitive data removed.

### Expected behavior

The command should set the connection string for application insights in the ACA environment.

### Environment Summary

az --version
azure-cli 2.65.0

core 2.65.0
telemetry 1.1.0

Extensions:
containerapp 1.0.0b4
ml 2.30.0
webpubsub 1.6.0

Dependencies:
msal 1.31.0
azure-mgmt-resource 23.1.1

Python location 'C:\Program Files (x86)\Microsoft SDKs\Azure\CLI2\python.exe'
Extensions directory 'C:\Users\mhurst\.azure\cliextensions'

Python (Windows) 3.11.8 (tags/v3.11.8:db85d51, Feb 6 2024, 21:52:07) [MSC v.1937 32 bit (Intel)]

Legal docs and information: aka.ms/AzureCliLegal

Your CLI is up-to-date.

### Additional context

_No response_