Fix equality operators.

src/ImageSharp/MetaData/Profiles/ICC/IccTagDataEntry.cs

@@ -56,7 +56,8 @@ namespace ImageSharp
                 return true;
             }
 
-            return this.Signature == other.Signature;
+            return this.Signature == other.Signature
+                && this.TagSignature == other.TagSignature;
         }
     }
 }

src/ImageSharp/MetaData/Profiles/ICC/Various/IccTagTableEntry.cs

@@ -73,7 +73,7 @@ namespace ImageSharp
         /// <inheritdoc/>
         public override bool Equals(object other)
         {
-            return (other is IccProfileId) && this.Equals((IccProfileId)other);
+            return (other is IccTagTableEntry) && this.Equals((IccTagTableEntry)other);
         }
 
         /// <inheritdoc/>