[bugfix] Fix double-click required after pasting URL in upload model dialog (#6801)

## Summary
Fixed an issue where users had to click twice to continue after pasting
a URL in the upload model dialog - once to blur the input, then again to
click the button.

## Changes
- **What**: Replaced `UrlInput` with plain `InputText` in
`UploadModelUrlInput` to emit value immediately on input instead of only
on blur
- **Cleanup**: Moved URL cleaning/normalization to the `fetchMetadata`
handler, removed unused `disableValidation` prop from `UrlInput`
component

## Review Focus
- URL normalization logic in `useUploadModelWizard.ts`

🤖 Generated with [Claude Code](https://claude.com/claude-code)

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-6801-bugfix-Fix-double-click-required-after-pasting-URL-in-upload-model-dialog-2b26d73d3650811881aed0cc064efcc7)
by [Unito](https://www.unito.io)

---------

Co-authored-by: Claude <noreply@anthropic.com>

src/platform/assets/components/UploadModelUrlInput.vue

@@ -14,10 +14,10 @@
       <label class="text-sm text-muted mb-0">
         {{ $t('assetBrowser.civitaiLinkLabel') }}
       </label>
-      <UrlInput
+      <InputText
         v-model="url"
         :placeholder="$t('assetBrowser.civitaiLinkPlaceholder')"
-        :disable-validation="true"
+        class="w-full"
       />
       <p v-if="error" class="text-xs text-error">
         {{ error }}
@@ -30,10 +30,9 @@
 </template>
 
 <script setup lang="ts">
+import InputText from 'primevue/inputtext'
 import { computed } from 'vue'
 
-import UrlInput from '@/components/common/UrlInput.vue'
-
 const props = defineProps<{
   modelValue: string
   error?: string