[TEST] Fix ext.http.curl.BasicCurlHttpTests.ElegantQuitQuick flaky test

[dbarker]

The following test is timing based and flaky in CI. This test should be fixed or disabled.

 898/1247 Test  #898: ext.http.curl.BasicCurlHttpTests.ElegantQuitQuick .........................................................................***Failed    0.05 sec
Running main() from /private/tmp/googletest-20250808-4877-y4cffa/googletest-1.17.0/googletest/src/gtest_main.cc
Note: Google Test filter = BasicCurlHttpTests.ElegantQuitQuick
[==========] Running 1 test from 1 test suite.
[----------] Global test environment set-up.
[----------] 1 test from BasicCurlHttpTests
[ RUN      ] BasicCurlHttpTests.ElegantQuitQuick
/Users/runner/work/opentelemetry-cpp/opentelemetry-cpp/ext/test/http/curl_http_test.cc:681: Failure
Value of: cost < std::chrono::milliseconds{20}
  Actual: false
Expected: true
cost ms: 21 libcurl version: 0x80600

[  FAILED  ] BasicCurlHttpTests.ElegantQuitQuick (43 ms)
[----------] 1 test from BasicCurlHttpTests (43 ms total)

[----------] Global test environment tear-down
[==========] 1 test from 1 test suite ran. (43 ms total)
[  PASSED  ] 0 tests.
[  FAILED  ] 1 test, listed below:
[  FAILED  ] BasicCurlHttpTests.ElegantQuitQuick

 1 FAILED TEST

[owent]

Could we increase the timeout here? GitHub CI runners sometimes schedule CPUs slowly, and a slightly higher timeout might help prevent flaky failures.