fix(flows): restore Variables and Resources in flow editor prop picker (#9290)

The design system overhaul in 888837431c accidentally dropped the
fallback condition that displayed the Variables and Resources sections
in the prop picker by default. After that commit, these sections only
appeared when the user typed `variable.` or `resource.` in their
expression, which meant they effectively disappeared from the flow
editor's prop picker for most users.

Restore the previous behavior by showing the sections when no input
match is active (the equivalent of the old `!filterActive` clause).

Fixes WIN-1976

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

frontend/src/lib/components/propertyPicker/PropPicker.svelte

@@ -375,7 +375,7 @@
 		{/if}
 
 		{#if displayContext}
-			{#if $inputMatches?.some((match) => match.word === 'variable')}
+			{#if !$inputMatches?.length || $inputMatches?.some((match) => match.word === 'variable')}
 				<span class={categoryTitleClasses}>Variables</span>
 				<div class={categoryContentClasses}>
 					{#if displayVariable}
@@ -412,7 +412,7 @@
 					{/if}
 				</div>
 			{/if}
-			{#if $inputMatches?.some((match) => match.word === 'resource')}
+			{#if !$inputMatches?.length || $inputMatches?.some((match) => match.word === 'resource')}
 				<span class={categoryTitleClasses}>Resources</span>
 				<div class={categoryContentClasses}>
 					{#if displayResources}