chore(bazel): update gapic-generator-php v1.4.4

Changes include:
- protect against diregapic enum using reserved words
- updated packaged version of composer and php for bazel

PiperOrigin-RevId: 428886122

WORKSPACE

@@ -296,7 +296,7 @@ yarn_install(
 ##############################################################################
 
 # PHP micro-generator
-_gapic_generator_php_version = "1.4.3"
+_gapic_generator_php_version = "1.4.4"
 
 http_archive(
     name = "gapic_generator_php",