Retain parsed attribute type

If the value of an attribute enum is defined as a hexadecimal integer,
flatten uses of the attribute as with the
android::Res_value::TYPE_INT_HEX type.

This change adds a "type" field to pb::Attribute::Symbol, which if left
unset, will have a default value of android::Res_value::TYPE_INT_DEC
when deserialized by aapt2.

Bug: 124474141
Test: aapt2_tests and manual compilation of files and inspection using
`aapt2 dump chunks`
Change-Id: Ibf12394284fdbe3a8047f7ecf4fe68517dfc3abb
diff --git a/tools/aapt2/ResourceParser.cpp b/tools/aapt2/ResourceParser.cpp
index 859fe80..c557656 100644
--- a/tools/aapt2/ResourceParser.cpp
+++ b/tools/aapt2/ResourceParser.cpp
@@ -1387,7 +1387,7 @@
 
   return Attribute::Symbol{
       Reference(ResourceNameRef({}, ResourceType::kId, maybe_name.value())),
-      val.data};
+      val.data, val.dataType};
 }
 
 bool ResourceParser::ParseStyleItem(xml::XmlPullParser* parser, Style* style) {