Fix handling of map adapters in expansion of const values

Summary:
Since the whole constant's value ends up being wrapped in `from_thrift(...)`:

https://www.internalfb.com/code/fbsource/[e4857a1da0accd0665a7ecf2cc85d98488e3986a]/fbcode/thrift/compiler/generate/templates/rust/lib/const.mustache?lines=37-41

the value we generate inside this cannot be the already-adapted type. It has to be the underlying Thrift type.

Reviewed By: capickett

Differential Revision: D66845279

fbshipit-source-id: ff6727a6e8e1bb37d458d2dd16f47d1e0b52a854

third-party/thrift/src/thrift/compiler/generate/templates/rust/lib/value.mustache

@@ -89,7 +89,10 @@
             }}{{#value:mapEntries}}
             {{value:indent}}{
                 {{value:indent}}#[inline(never)]
-                {{value:indent}}fn __do_insert(map: &mut {{>lib/rawtype}}) {
+                {{value:indent}}fn __do_insert(map: &mut {{!
+                    }}{{#type:has_adapter?}}{{>lib/adapter/qualified}}::StandardType{{/type:has_adapter?}}{{!
+                    }}{{^type:has_adapter?}}{{>lib/type}}{{/type:has_adapter?}}{{!
+                }}) {
                     {{value:indent}}map.insert({{!
                         }}{{#entry:key}}{{!
                             }}{{#value:floatingPoint?}}{{!