docs: Remove unnecessary Flask app (#570)

The current auto instrumentation example includes an unnecessary Flask app in its client.

Author: ocelotl

docs/examples/auto-instrumentation/client.py

@@ -14,7 +14,6 @@
 
 from sys import argv
 
-from flask import Flask
 from requests import get
 
 from opentelemetry import propagators, trace
@@ -24,8 +23,6 @@
     SimpleExportSpanProcessor,
 )
 
-app = Flask(__name__)
-
 trace.set_tracer_provider(TracerProvider())
 tracer = trace.get_tracer_provider().get_tracer(__name__)