Add SK_SUPPORT_LEGACY_IMAGEFILTER_PTR to public.bzl DEFINES to fix build.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1853773002

Review URL: https://codereview.chromium.org/1853773002
diff --git a/public.bzl b/public.bzl
index 14a66a7..bf163d0 100644
--- a/public.bzl
+++ b/public.bzl
@@ -534,14 +534,15 @@
     # Chrome DEFINES.
     "SK_USE_FLOATBITS",
     "SK_USE_FREETYPE_EMBOLDEN",
-    "SK_SUPPORT_LEGACY_NEW_SURFACE_API",
-    "SK_SUPPORT_LEGACY_MINOR_EFFECT_PTR",
-    "SK_SUPPORT_LEGACY_PATHEFFECT_PTR",
     # Turn on a few Google3-specific build fixes.
     "GOOGLE3",
     # Staging flags for API changes
     "SK_SUPPORT_LEGACY_COLORFILTER_PTR",
     "SK_SUPPORT_LEGACY_CREATESHADER_PTR",
+    "SK_SUPPORT_LEGACY_IMAGEFILTER_PTR",
+    "SK_SUPPORT_LEGACY_MINOR_EFFECT_PTR",
+    "SK_SUPPORT_LEGACY_NEW_SURFACE_API",
+    "SK_SUPPORT_LEGACY_PATHEFFECT_PTR",
     "SK_SUPPORT_LEGACY_PICTURE_PTR",
     "SK_SUPPORT_LEGACY_XFERMODE_PTR",
 ]