Fix typo in OnlySampleTranformContentToDecode (#3037)

tests/gtest/avifaltrtest.cc

diff --git a/tests/gtest/avifaltrtest.cc b/tests/gtest/avifaltrtest.cc
index ee96515..17575cc 100644
--- a/tests/gtest/avifaltrtest.cc
+++ b/tests/gtest/avifaltrtest.cc
@@ -86,7 +86,7 @@
             AVIF_RESULT_NO_CONTENT);
 }
 
-TEST(AltrTest, OnlySampleTranformContentToDecode) {
+TEST(AltrTest, OnlySampleTransformContentToDecode) {
   const std::string file_path =
       std::string(data_path) + "weld_sato_12B_8B_q0.avif";