[GitHub] Remove Architecture from the issue template (#4543)

## Description

Removes the `Architecture` dropdown from the issue template. The New
Architecture is enabled by default and is the only one the library
supports, so the answer carries no useful information.

## Test plan

Open the "New issue" form on GitHub and confirm the bug report renders
without the Architecture field.

Author: j-piasecki

.github/ISSUE_TEMPLATE/bug-report.yml

@@ -109,15 +109,6 @@ body:
         - Using Expo Go
         - Using Expo Prebuild or an Expo development build
 
-  - type: dropdown
-    id: architecture
-    attributes:
-      label: Architecture
-      description: What React Native architecture your application is running on? Currently, the New Architecture is enabled by default for every new React Native project.
-      options:
-        - New Architecture (Fabric)
-        - Old Architecture (Paper)
-
   - type: dropdown
     id: build-type
     attributes: