For images that include SMask/Mask entries, ignore an SMask defined in the current graphics state

From section [11.6.4.3 Mask Shape and Opacity](https://opensource.adobe.com/dc-acrobat-sdk-docs/pdfstandards/PDF32000_2008.pdf#G10.4848628) in the PDF specification:
 - An image XObject may contain its own *soft-mask image* in the form of a subsidiary image XObject in the `SMask` entry of the image dictionary (see "Image Dictionaries"). This mask, if present, shall override any explicit or colour key mask specified by the image dictionary's `Mask` entry. Either form of mask in the image dictionary shall override the current soft mask in the graphics state.

test/pdfs/.gitignore

@@ -232,6 +232,7 @@
 !issue5954.pdf
 !issue6612.pdf
 !alphatrans.pdf
+!issue14200.pdf
 !pattern_text_embedded_font.pdf
 !devicen.pdf
 !cmykjpeg.pdf

test/test_manifest.json

@@ -5255,6 +5255,13 @@
     "link": true,
     "type": "eq"
   },
+  {
+    "id": "issue14200",
+    "file": "pdfs/issue14200.pdf",
+    "md5": "4dba2cde1c6e65abe53e66eefc97a7f1",
+    "rounds": 1,
+    "type": "eq"
+  },
   {
     "id": "jbig2_huffman_1",
     "file": "pdfs/jbig2_huffman_1.pdf",