Style: Standardize icon use Part 1 (#5947)

## Summary

Remove the mix of class based and component style icons in favor of just
[classes](https://iconify.design/docs/usage/css/tailwind/tailwind4/#basic-usage).

## Changes

- **What**: Migrate existing lucide icons

## Review Focus

What differs between the icons before and now?

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-5947-Style-Standardize-icon-use-Part-1-2846d73d365081bfa66ceb6bdaa9ff02)
by [Unito](https://www.unito.io)

---------

Co-authored-by: github-actions <github-actions@github.com>

src/components/custom/widget/WorkflowTemplateSelectorDialog.vue

@@ -29,7 +29,7 @@
           @click="resetFilters"
         >
           <template #icon>
-            <i-lucide:filter-x />
+            <i class="icon-[lucide--filter-x]" />
           </template>
         </IconTextButton>
       </div>
@@ -49,7 +49,7 @@
           :show-clear-button="true"
         >
           <template #icon>
-            <i-lucide:cpu />
+            <i class="icon-[lucide--cpu]" />
           </template>
         </MultiSelect>
 
@@ -63,7 +63,7 @@
           :show-clear-button="true"
         >
           <template #icon>
-            <i-lucide:target />
+            <i class="icon-[lucide--target]" />
           </template>
         </MultiSelect>
 
@@ -77,7 +77,7 @@
           :show-clear-button="true"
         >
           <template #icon>
-            <i-lucide:file-text />
+            <i class="icon-[lucide--file-text]" />
           </template>
         </MultiSelect>
 
@@ -90,7 +90,7 @@
             class="min-w-[270px]"
           >
             <template #icon>
-              <i-lucide:arrow-up-down />
+              <i class="icon-[lucide--arrow-up-down]" />
             </template>
           </SingleSelect>
         </div>
@@ -111,7 +111,7 @@
         v-if="!isLoading && filteredTemplates.length === 0"
         class="flex flex-col items-center justify-center h-64 text-neutral-500"
       >
-        <i-lucide:search class="w-12 h-12 mb-4 opacity-50" />
+        <i class="icon-[lucide--search] w-12 h-12 mb-4 opacity-50" />
         <p class="text-lg mb-2">
           {{ $t('templateWorkflows.noResults', 'No templates found') }}
         </p>