Copilot Chat: align bash deploy-webapi script with powershell (micros…

…oft#1786)

### Motivation and Context
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I noticed the script was slightly misaligned during my deployment of
webapi.

### Description
<!-- Describe your changes, the overall approach, the underlying design.
These notes will help understanding how your code works. Thanks! -->
corrects the usage string and sets a default value for the
`PACKAGE_FILE_PATH` similar to the Powershell script.

### Contribution Checklist
<!-- Before submitting this PR, please make sure: -->
- [X] The code builds clean without any errors or warnings
- [X] The PR follows SK Contribution Guidelines
(https://github.com/microsoft/semantic-kernel/blob/main/CONTRIBUTING.md)
- [X] The code follows the .NET coding conventions
(https://learn.microsoft.com/dotnet/csharp/fundamentals/coding-style/coding-conventions)
verified with `dotnet format`
- [X] All unit tests pass, and I have added new tests where possible
- [X] I didn't break anyone 😄

samples/apps/copilot-chat-app/deploy/deploy-webapi.sh

@@ -5,13 +5,13 @@
 set -e
 
 usage() {
-    echo "Usage: $0 -d DEPLOYMENT_NAME -s SUBSCRIPTION --ai AI_SERVICE_TYPE -aikey AI_SERVICE_KEY [OPTIONS]"
+    echo "Usage: $0 -d DEPLOYMENT_NAME -s SUBSCRIPTION -rg RESOURCE_GROUP [OPTIONS]"
     echo ""
     echo "Arguments:"
-    echo "  -s, --subscription SUBSCRIPTION        Subscription to which to make the deployment (mandatory)"
+    echo "  -d, --deployment-name DEPLOYMENT_NAME   Name of the deployment from a 'deploy-azure.sh' deployment (mandatory)"
+    echo "  -s, --subscription SUBSCRIPTION         Subscription to which to make the deployment (mandatory)"
     echo "  -rg, --resource-group RESOURCE_GROUP    Resource group name from a 'deploy-azure.sh' deployment (mandatory)"
-    echo "  -d, --deployment-name DEPLOYMENT_NAME  Name of the deployment from a 'deploy-azure.sh' deployment (mandatory)"
-    echo "  -p, --package PACKAGE_FILE_PATH        Path to the WebAPI package file from a 'package-webapi.sh' run (mandatory)"
+    echo "  -p, --package PACKAGE_FILE_PATH         Path to the WebAPI package file from a 'package-webapi.sh' run"
 }
 
 # Parse arguments
@@ -47,11 +47,14 @@ while [[ $# -gt 0 ]]; do
 done
 
 # Check mandatory arguments
-if [[ -z "$DEPLOYMENT_NAME" ]] || [[ -z "$SUBSCRIPTION" ]] || [[ -z "$RESOURCE_GROUP" ]] || [[ -z "$PACKAGE_FILE_PATH" ]]; then
+if [[ -z "$DEPLOYMENT_NAME" ]] || [[ -z "$SUBSCRIPTION" ]] || [[ -z "$RESOURCE_GROUP" ]]; then
     usage
     exit 1
 fi
 
+# Set defaults
+: "${PACKAGE_FILE_PATH:="$(dirname "$0")/out/webapi.zip"}"
+
 # Ensure $PACKAGE_FILE_PATH exists
 if [[ ! -f "$PACKAGE_FILE_PATH" ]]; then
     echo "Package file '$PACKAGE_FILE_PATH' does not exist. Have you run 'package-webapi.sh' yet?"