rtsp: test elements_rtpsession.test_multiple_senders_roundrobin_rbs occasionally fails

CI Log: https://gitlab.freedesktop.org/alatiera/gst-ci/-/jobs/77533

Output

check.gst-plugins-good.elements_rtpsession.test_multiple_senders_roundrobin_rbs: Failed 'Application returned 1'
       You can reproduce with: GST_PLUGIN_LOADING_WHITELIST='gstreamer:gst-plugins-base:gst-plugins-good@/builds/alatiera/gst-ci/gst-build/build' GST_PLUGIN_PATH_1_0='/builds/alatiera/gst-ci/gst-build/build' GST_PLUGIN_SYSTEM_PATH_1_0='' GST_REGISTRY='/builds/alatiera/gst-ci/gst-build/build/subprojects/gst-plugins-good/tests/check/elements_rtpsession.registry' GST_STATE_IGNORE_ELEMENTS='aasink autoaudiosrc autoaudiosink autovideosrc
 autovideosink cacasink cairotextoverlay jackaudiosrc jackaudiosink
 osssrc osssink osxaudiosink osxaudiosrc osxvideosrc osxvideosink
 pulsesink pulsesrc pulsemixer v4l2src' GST_CHECKS='test_multiple_senders_roundrobin_rbs' CK_DEFAULT_TIMEOUT='20' /builds/alatiera/gst-ci/gst-build/build/subprojects/gst-plugins-good/tests/check/elements_rtpsession

Dumping log files on failure

Dumping contents of /builds/alatiera/gst-ci/validate-output/logs/check/gst-plugins-good/elements_rtpsession/test_multiple_senders_roundrobin_rbs

=================
Test name: check.gst-plugins-good.elements_rtpsession.test_multiple_senders_roundrobin_rbs
Command: '/builds/alatiera/gst-ci/gst-build/build/subprojects/gst-plugins-good/tests/check/elements_rtpsession'
=================

Running suite(s): rtpsession
0%: Checks: 1, Failures: 1, Errors: 0
../subprojects/gst-plugins-good/tests/check/elements/rtpsession.c:343:F:general:test_multiple_senders_roundrobin_rbs:0: 'expected_rb_count' (4) is not equal to 'gst_rtcp_packet_get_rb_count (&rtcp_packet)' (0)
Check suite rtpsession ran in 0.019s (tests failed: 1)