Fix typo in Agent365Exporter class docstring

Author: pontemonti

libraries/microsoft-agents-a365-observability-core/microsoft_agents_a365/observability/core/exporters/agent365_exporter.py

@@ -37,7 +37,7 @@
 
 class Agent365Exporter(SpanExporter):
     """
-    Agent365 span exporter for Agent365:
+    Agent 365 span exporter for Agent 365:
       * Partitions spans by (tenantId, agentId)
       * Builds OTLP-like JSON: resourceSpans -> scopeSpans -> spans
       * POSTs per group to https://{endpoint}/maven/agent365/agents/{agentId}/traces?api-version=1