Remove explorer from issue templates (#4945)

.github/ISSUE_TEMPLATE/01_explorer_bug.yml

@@ -1,44 +0,0 @@
-# Part of the Carbon Language project, under the Apache License v2.0 with LLVM
-# Exceptions. See /LICENSE for license information.
-# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-
-name: Carbon Explorer bug
-description: >
-  Report a bug with the Carbon Explorer interpreter. This is what's provided at
-  [Compiler Explorer](https://carbon.compiler-explorer.com).
-labels: [explorer]
-body:
-  - type: markdown
-    attributes:
-      value: >
-        **Attention:** If this is a _question_, please use either [GitHub
-        Discussions](https://github.com/carbon-language/carbon-lang/discussions)
-        or [Discord](https://discord.gg/ZjVdShJDAs).
-  - type: textarea
-    id: desc
-    attributes:
-      label: >
-        Description of the bug:
-  - type: textarea
-    id: repro
-    attributes:
-      label: >
-        What did you do, or what's a simple way to reproduce the bug?
-      description: >
-        Please provide example code and errors; a shortlink to the execution on
-        [Compiler Explorer](https://carbon.compiler-explorer.com) can also help.
-  - type: textarea
-    id: expected
-    attributes:
-      label: >
-        What did you expect to happen?
-  - type: textarea
-    id: actual
-    attributes:
-      label: >
-        What actually happened?
-  - type: textarea
-    id: extras
-    attributes:
-      label: >
-        Any other information, logs, or outputs that you want to share?