Default App Service end-to-end encryption to enabled

### Summary

Aspire-generated Azure App Service infrastructure should set `properties.endToEndEncryptionEnabled` to `true` by default.

### Motivation

While hardening the aspire.dev deployment, each App Service site had to opt into end-to-end TLS explicitly. Making this the framework default gives Aspire applications the secure configuration without requiring every deployment to repeat the setting.

### Proposed behavior

- Generated Bicep for Azure App Service sites sets `endToEndEncryptionEnabled: true` by default.
- An explicit user configuration can override the default if an opt-out is required for compatibility.
- Provisioning tests verify the generated property and override behavior.

Start by locating the Azure App Service Bicep generation entry point and the provisioning tests. Verify that generated sites set endToEndEncryptionEnabled to true by default, then confirm the tests cover an explicit user override; done means both default and opt-out behavior are validated.

Written by the indexing model from the issue text.