LoRa: ask for the frame bound before reading back the CR it timed

test_preambleHold_isSizedForTheWorstCaseFrame read phy.lastCodingRate
straight after the first preamble sighting, where nothing has yet asked
the chip to time anything: preambleHoldActive() short-circuits on the
unset stamp, so the sighting that starts a hold never reaches
calculateTimeOnAir() and the fake still reports a coding rate of 0.

Ask maxRxFrameMsec() for the bound first, then assert the CR and CRC it
was asked for. The case pins the same thing it always meant to - that the
hold is timed at CR 4/8 with CRC rather than at our own CR.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CStem6K6MQRBNR8YCFgtCE

test/test_radio/test_main.cpp

@@ -789,9 +789,11 @@ static void test_preambleHold_isSizedForTheWorstCaseFrame()
 
     Time::setTestMillis(1000);
     TEST_ASSERT_TRUE(radioIf->receiveDetectedPublic(TestableRadioLibInterface::kFakePreambleDetected));
+    // The first sighting short-circuits on the unset stamp, so the bound has to be asked for before the chip has been
+    // asked anything at all.
+    TEST_ASSERT_EQUAL_UINT32_MESSAGE(159, radioIf->maxRxFrameMsecPublic(), "part milliseconds round up");
     TEST_ASSERT_EQUAL_UINT8_MESSAGE(8, phy.lastCodingRate, "the hold must be timed at the worst case CR, not ours");
     TEST_ASSERT_TRUE_MESSAGE(phy.lastCrcEnabled, "a received frame may carry a CRC, which lengthens it");
-    TEST_ASSERT_EQUAL_UINT32_MESSAGE(159, radioIf->maxRxFrameMsecPublic(), "part milliseconds round up");
 
     Time::setTestMillis(1100); // the old sizing released here, with the frame still arriving
     TEST_ASSERT_TRUE(radioIf->preambleHoldActivePublic());