refactor(utils): remove isServer (#5173)

packages/hooks/use-id/index.ts

@@ -1,5 +1,5 @@
 import { computed, inject, unref } from 'vue'
-import isServer from '@element-plus/utils/isServer'
+import { isClient } from '@vueuse/core'
 import { debugWarn } from '@element-plus/utils/error'
 
 import type { InjectionKey, Ref } from 'vue'
@@ -21,7 +21,7 @@ export const ID_INJECTION_KEY: InjectionKey<ElIdInjectionContext> =
 export const useId = (deterministicId?: MaybeRef<string>): Ref<string> => {
   const idInjection = inject(ID_INJECTION_KEY, defaultIdInjection)
 
-  if (isServer && idInjection === defaultIdInjection) {
+  if (!isClient && idInjection === defaultIdInjection) {
     debugWarn(
       'IdInjection',
       `Looks like you are using server rendering, you must provide a id provider to ensure the hydration process to be succeed

packages/hooks/use-popper-container/index.ts

@@ -1,6 +1,6 @@
 import { onBeforeMount } from 'vue'
+import { isClient } from '@vueuse/core'
 import { generateId } from '@element-plus/utils/util'
-import isServer from '@element-plus/utils/isServer'
 
 let cachedContainer: HTMLElement
 
@@ -10,7 +10,7 @@ export const POPPER_CONTAINER_SELECTOR = `#${POPPER_CONTAINER_ID}`
 
 export const usePopperContainer = () => {
   onBeforeMount(() => {
-    if (isServer) return
+    if (!isClient) return
 
     // This is for bypassing the error that when under testing env, we often encounter
     // document.body.innerHTML = '' situation

packages/utils/isServer.ts

@@ -1 +0,0 @@
-export default !(globalThis ? globalThis.document : window)