fix(devtools-kit): remove special handling for Router object

[skirtles-code]

There's currently some special handling for rendering a Vue Router instance. However...

1. The check for val.constructor.name === 'VueRouter' is for the Vue 2 router, so it doesn't do anything with Vue 3. The code involving getRouterDetails doesn't actually run.
2. The other relevant code path in replacer.ts returns '[object Router]', which isn't very helpful (see Before screenshot below).

I had originally intended to fix that second code path to call getRouterDetails, which did work, but it then occurred to me that none of this is really necessary. Maybe at some point in the past there were issues displaying the router instance, but just treating it like any other object works fine now.

Before:

After:

[netlify]

✅ Deploy Preview for vue-devtools-docs canceled.

Name	Link
🔨 Latest commit	5e1cb75
🔍 Latest deploy log	https://app.netlify.com/projects/vue-devtools-docs/deploys/69ed058fc4da6f0009f810f2

[pkg-pr-new]

Open in StackBlitz

@vue/devtools-applet

npm i https://pkg.pr.new/@vue/devtools-applet@1092

@vue/devtools-core

npm i https://pkg.pr.new/@vue/devtools-core@1092

@vue/devtools

npm i https://pkg.pr.new/@vue/devtools@1092

@vue/devtools-api

npm i https://pkg.pr.new/@vue/devtools-api@1092

@vue/devtools-kit

npm i https://pkg.pr.new/@vue/devtools-kit@1092

@vue/devtools-electron

npm i https://pkg.pr.new/@vue/devtools-electron@1092

@vue/devtools-shared

npm i https://pkg.pr.new/@vue/devtools-shared@1092

@vue/devtools-ui

npm i https://pkg.pr.new/@vue/devtools-ui@1092

vite-plugin-vue-devtools

npm i https://pkg.pr.new/vite-plugin-vue-devtools@1092

commit: 5e1cb75