fix(userspace/libsinsp): keep event thread after execve #7219

Job	Run time
build-libs-linux-amd64-static 🎃	22m 59s
build-libs-linux-amd64 😁 (system_deps)	6m 51s
build-libs-others-amd64 😨 (windows-latest, MultiThreaded)	5m 40s
build-libs-linux-amd64 😁 (bundled_deps)	16m 34s
build-shared-libs-linux-amd64 🧐	5m 53s
build-libs-others-amd64 😨 (windows-latest, MultiThreadedDLL)	5m 42s
build-shared-libs-macos-amd64 😨	1m 6s
build-libs-linux-amd64 😁 (system_deps_minimal)	5m 23s
build-libs-others-amd64 😨 (macos-latest)	2m 27s
build-libs-linux-amd64 😁 (sanitizers)	15m 37s
test-libs-static (bundled_deps)	14m 27s
build-libs-linux-amd64 😁 (zig)	26m 38s
build-libs-linux-arm64 😁 (system_deps)	11m 17s
run-e2e-tests-amd64 (system_deps)	8m 51s
build-libs-emscripten 🧐	5m 40s
build-libs-linux-arm64 😁 (bundled_deps)	26m 20s
run-e2e-tests-amd64 (bundled_deps)	19m 4s
build-libs-linux-arm64 😁 (system_deps_minimal)	8m 48s
run-e2e-tests-amd64 (asan)	20m 49s
build-libs-linux-arm64 😁 (sanitizers)	31m 10s
build-libs-linux-arm64 😁 (zig)	41m 10s
	5h 2m 26s

Provide feedback