Fix letsencrypt missing parameters

Fixes #3638

Update `core/terraform/outputs.sh` to handle empty `tre_output.json` file

* Add a check to see if `tre_output.json` is empty
* If `tre_output.json` is empty, run `terraform init` to recreate it

---

For more details, open the [Copilot Workspace session](https://copilot-workspace.githubnext.com/microsoft/AzureTRE/issues/3638?shareId=XXXX-XXXX-XXXX-XXXX).

core/terraform/outputs.sh

@@ -1,7 +1,7 @@
 #!/bin/bash
 set -e
 
-if [ ! -f ../tre_output.json ]; then
+if [ ! -f ../tre_output.json ] || [ ! -s ../tre_output.json ]; then
   # Connect to the remote backend of Terraform
   export TF_LOG=""
   # shellcheck disable=SC2154