Revert "Add-ons: Add alert warning to PNGTranslator"

This reverts commit 450208975b.

The alert is not appropriate because applications cannot intercept it.

Fixes #15734

Change-Id: I5be98367ae615a572193406a559e5d34617e445c
Reviewed-on: https://review.haiku-os.org/c/haiku/+/2626
Reviewed-by: waddlesplash <[email protected]>

src/add-ons/translators/png/PNGTranslator.cpp

@@ -36,7 +36,6 @@
 #include <stdio.h>
 #include <string.h>
 
-#include <Alert.h>
 #include <Catalog.h>
 #include <OS.h>
 #define PNG_NO_PEDANTIC_WARNINGS
@@ -300,11 +299,9 @@ void throw_error(png_structp ppng, png_const_charp error_msg)
 
 void alert_warning(png_structp ppng, png_const_charp error_msg)
 {
-	BAlert* alert = new BAlert("alert", error_msg,
-		B_TRANSLATE("OK"), NULL, NULL, B_WIDTH_FROM_LABEL,
-		B_WARNING_ALERT);
-	alert->SetFlags(alert->Flags() | B_CLOSE_ON_ESCAPE);
-	alert->Go();
+	// These are only warnings and the image can still be decoded. We have no
+	// way to convey this to the calling app using the current translator API,
+	// so the warnings are just ignored.
 }
 
 status_t