refactor: re-use existed escapeRegex (#34470)

## Bug

- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Errors have helpful link attached, see `contributing.md`

## Feature

- [ ] Implements an existing feature request or RFC. Make sure the feature request has been accepted for implementation before opening a PR.
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Documentation added
- [ ] Telemetry added. In case of a feature if it's used or not.
- [ ] Errors have helpful link attached, see `contributing.md`

## Documentation / Examples

- [x] Make sure the linting passes by running `yarn lint`

`escape-regex.ts` will always be included in the bundle, so not re-using it actually makes the size larger.

packages/next/shared/lib/router/utils/route-regex.ts

@@ -1,15 +1,11 @@
+import { escapeStringRegexp } from '../../escape-regexp'
+
 interface Group {
   pos: number
   repeat: boolean
   optional: boolean
 }
 
-// this isn't importing the escape-string-regex module
-// to reduce bytes
-function escapeRegex(str: string) {
-  return str.replace(/[|\\{}()[\]^$+*?.-]/g, '\\$&')
-}
-
 function parseParameter(param: string) {
   const optional = param.startsWith('[') && param.endsWith(']')
   if (optional) {
@@ -34,7 +30,7 @@ export function getParametrizedRoute(route: string) {
         groups[key] = { pos: groupIndex++, repeat, optional }
         return repeat ? (optional ? '(?:/(.+?))?' : '/(.+?)') : '/([^/]+?)'
       } else {
-        return `/${escapeRegex(segment)}`
+        return `/${escapeStringRegexp(segment)}`
       }
     })
     .join('')
@@ -92,7 +88,7 @@ export function getParametrizedRoute(route: string) {
               : `/(?<${cleanedKey}>.+?)`
             : `/(?<${cleanedKey}>[^/]+?)`
         } else {
-          return `/${escapeRegex(segment)}`
+          return `/${escapeStringRegexp(segment)}`
         }
       })
       .join('')