[ROCm][CI] Stabilize Granite tool-use and test URL construction (#43017)

Signed-off-by: Andreas Karatzas <akaratza@amd.com>

examples/tool_chat_template_granite.jinja

@@ -1,4 +1,8 @@
 {%- if tools %}
+    {%- if messages and messages[0]['role'] != 'system' %}
+        {{- '<|start_of_role|>system<|end_of_role|>You are a helpful AI assistant with access to the following tools. When a tool is required to answer the user query, respond with <|tool_call|> followed by a JSON list of tools used.<|end_of_text|>
+' }}
+    {%- endif %}
     {{- '<|start_of_role|>available_tools<|end_of_role|>
 ' }}
     {%- for tool in tools %}