Update python:3.15.2 Docker digest to d7a732b

Author: renovate[bot]

ext/test/w3c_tracecontext_http_test_server/Dockerfile

@@ -1,7 +1,7 @@
 # Copyright The OpenTelemetry Authors
 # SPDX-License-Identifier: Apache-2.0
 
-FROM python:3.15.2@sha256:7f5f45581923aecdbf26eca1df56b2b7f6f99757fbec990ae944f15fc136efdc
+FROM python:3.15.2@sha256:d7a732b20de2f5d3cf977cbcf69aacf30dc928a37908ff9fdb7bb3503024c91a
 
 RUN pip install aiohttp
 RUN git clone https://github.com/w3c/trace-context