Fix a bug with mojom imports where 2 imports with the same namespace would

mojo/public/bindings/generators/js_templates/struct_definition.tmpl

 {%- macro set_default(kind, value, depth) -%}
 {#--- Strings ---#}
 {%-   if kind|is_string_kind -%}
 {{caller(value)}}
 {#--- Arrays ---#}
 {%-   elif kind|is_array_kind %}
 {%-     set _ = value|verify_token_type("ARRAY") %}
 {
   var tmp{{depth}} = [];
 {%-     for element in value[1] %}
@@ skipping 17 matching lines @@
 {%-     filter indent(2) %}
 {%-       call(result) set_default(subfield.kind, element, depth+1) %}
 tmp{{depth}}.{{subfield.name}} = {{result}};
 {%-       endcall %}
 {%-     endfilter %}
 {%-   endfor -%}
   {{caller("tmp" ~ depth)|indent(2)}}
 }
 {#--- POD types ---#}
 {%-   else -%}
-{{caller(value)}}
+{{caller(value|substitute_namespace(imports))}}
 {%-   endif %}
 {%- endmacro %}
 
 
   function {{struct.name}}() {
 {%- for packed_field in struct.packed.packed_fields %}
 {%- if packed_field.field.default %}
 {%-   filter indent(4) %}
 {%-     call(result) set_default(packed_field.field.kind, packed_field.field.default, 0) %}
 this.{{packed_field.field.name}} = {{result}};
@@ skipping 52 matching lines @@
 {%-   else %}
 {%-     for packed_field in byte.packed_fields %}
     encoder.{{packed_field.field.kind|encode_snippet}}val.{{packed_field.field.name}});
 {%-     endfor %}
 {%-   endif %}
 {%-   if byte.is_padding %}
     encoder.skip(1);
 {%-   endif %}
 {%- endfor %}
   };