feat: FeDropShadow (#2514)

# Summary

Continuation of #2362 introducing highly requested ✨ `FeDropShadow` ✨
filter. This addition is straightforward since it's essentially a
shorthand (as specified in the spec) for filters that are already
implemented: https://www.w3.org/TR/filter-effects-1/#feDropShadowElement

<img width="532" alt="image"
src="https://github.com/user-attachments/assets/b221ee4c-d8b0-469b-acb0-71224fb2b1e0">

## Test Plan

Example app -> Filters -> FeDropShadow

## Compatibility

| OS      | Implemented |
| ------- | :---------: |
| iOS     |    ✅      |
| macOS   |    ✅      |
| Android |    ✅      |
| Web     |    ✅      |

src/elements/filters/FeDropShadow.tsx

@@ -1,12 +1,20 @@
+import { ColorValue } from 'react-native';
 import { NumberArray, NumberProp } from '../../lib/extract/types';
-import { warnUnimplementedFilter } from '../../lib/util';
+import FeFlood from './FeFlood';
+import FeGaussianBlur from './FeGaussianBlur';
+import FeMerge from './FeMerge';
+import FeMergeNode from './FeMergeNode';
+import FeOffset from './FeOffset';
 import FilterPrimitive from './FilterPrimitive';
+import FeComposite from './FeComposite';
 
 export interface FeDropShadowProps {
   in?: string;
   stdDeviation?: NumberArray;
   dx?: NumberProp;
   dy?: NumberProp;
+  floodColor?: ColorValue;
+  floodOpacity?: NumberProp;
 }
 
 export default class FeDropShadow extends FilterPrimitive<FeDropShadowProps> {
@@ -17,7 +25,21 @@ export default class FeDropShadow extends FilterPrimitive<FeDropShadowProps> {
   };
 
   render() {
-    warnUnimplementedFilter();
-    return null;
+    const { stdDeviation, in: in1 = 'SourceGraphic', dx, dy } = this.props;
+    return (
+      <>
+        <FeGaussianBlur in={in1} stdDeviation={stdDeviation} />
+        <FeOffset dx={dx} dy={dy} result="offsetblur" />
+        <FeFlood
+          floodColor={this.props.floodColor}
+          floodOpacity={this.props.floodOpacity}
+        />
+        <FeComposite in2="offsetblur" operator="in" />
+        <FeMerge>
+          <FeMergeNode />
+          <FeMergeNode in={in1} />
+        </FeMerge>
+      </>
+    );
   }
 }