test(player): match the renamed carrier diagnostic in the mismatch regression

The rate-mismatch regression greps the audio diagnostics for the literal
'MAT/IEC 61937 carrier', but 658469f9 reworded the sink's engage message to
'TrueHD (MAT) via IEC 61937 carrier' when DTS-HD joined the carrier. The test
self-skips on carrier-less CI emulators, so the rot only surfaces on real
hardware, where the fallback behaves correctly and the assertion still fails.
Match the shared 'via IEC 61937 carrier' fragment both codecs emit.

android/app/src/androidTest/kotlin/com/edde746/plezy/exoplayer/TrueHdSpeedTransitionTest.kt

@@ -297,7 +297,7 @@ class TrueHdSpeedTransitionTest {
     // AudioTrack is ever opened and the rate sequence alone cannot tell the two apart.
     assertTrue(
       "the carrier must have been entered and then left at runtime, saw: $diagnostics",
-      diagnostics.any { it.contains("MAT/IEC 61937 carrier") } &&
+      diagnostics.any { it.contains("via IEC 61937 carrier") } &&
         diagnostics.any { it.contains("44.1kHz-family rate its container did not") }
     )
     assertTrue("a decoder must take the stream over instead of the carrier", decoder != null)