feat: add FeMerge and FeMergeNode filters (#2369)

# Summary

As mentioned in #2362
Introduce new filters:
* `FeMerge`
* `FeMergeNode`

## Example usage

```tsx
<Svg width="200" height="200">
  <Filter id="mergeWithOffset" width="180" height="180">
    <FeOffset dx="50" dy="50" result="test" />
    <FeOffset dx="100" dy="100" in="SourceGraphic" />
    <FeMerge>
      <FeMergeNode in="SourceGraphic" />
      <FeMergeNode in="test" />
      <FeMergeNode />
    </FeMerge>
  </Filter>
  <Rect
    x="0"
    y="0"
    width="100"
    height="100"
    stroke="black"
    fill="red"
    filter="url(#mergeWithOffset)"
  />
</Svg>
```

<img width="207" alt="image"
src="https://github.com/user-attachments/assets/9cb3ded6-f939-4b2b-8ece-df54e64fe898">

## Test Plan

`Example` app -> `Filters` -> `FeMerge`

## Compatibility

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

## Checklist

- [x] I have tested this on a device and a simulator
- [x] I added documentation in `README.md`
- [x] I updated the typed files (typescript)

apple/ViewManagers/RNSVGFeMergeManager.h

@@ -0,0 +1,5 @@
+#import "RNSVGFilterPrimitiveManager.h"
+
+@interface RNSVGFeMergeManager : RNSVGFilterPrimitiveManager
+
+@end

apple/ViewManagers/RNSVGFeMergeManager.mm

@@ -0,0 +1,15 @@
+#import "RNSVGFeMergeManager.h"
+#import "RNSVGFeMerge.h"
+
+@implementation RNSVGFeMergeManager
+
+RCT_EXPORT_MODULE()
+
+- (RNSVGFeMerge *)node
+{
+  return [RNSVGFeMerge new];
+}
+
+RCT_EXPORT_VIEW_PROPERTY(nodes, NSArray<NSString *>)
+
+@end