fix: provide theme to SvgAssetLoader instead of SvgPicture (#532)

## What does this change?

Since version 5.5.0+1, the `SvgTheme` no longer works. It doesn't work because flutter_svg has deprecated using the `theme` with the `SvgPicture` constructor, and suggests that you pass the theme to the bytes loader instead.

Fixes #531  🎯

## Type of change

- [x] Bug fix (non-breaking change which fixes an issue)

examples/example/lib/gen/assets.gen.dart

@@ -318,7 +318,7 @@ class SvgGenImage {
  ? AssetBytesLoader(_assetName,
  assetBundle: bundle, packageName: package)
  : SvgAssetLoader(_assetName,
- assetBundle: bundle, packageName: package),
+ assetBundle: bundle, packageName: package, theme: theme),
  key: key,
  matchTextDirection: matchTextDirection,
  width: width,
@@ -329,7 +329,6 @@ class SvgGenImage {
  placeholderBuilder: placeholderBuilder,
  semanticsLabel: semanticsLabel,
  excludeFromSemantics: excludeFromSemantics,
- theme: theme,
  colorFilter: colorFilter ??
  (color == null ? null : ColorFilter.mode(color, colorBlendMode)),
  clipBehavior: clipBehavior,

examples/example_resources/lib/gen/assets.gen.dart

@@ -186,7 +186,7 @@ class SvgGenImage {
  ? AssetBytesLoader(_assetName,
  assetBundle: bundle, packageName: package)
  : SvgAssetLoader(_assetName,
- assetBundle: bundle, packageName: package),
+ assetBundle: bundle, packageName: package, theme: theme),
  key: key,
  matchTextDirection: matchTextDirection,
  width: width,
@@ -197,7 +197,6 @@ class SvgGenImage {
  placeholderBuilder: placeholderBuilder,
  semanticsLabel: semanticsLabel,
  excludeFromSemantics: excludeFromSemantics,
- theme: theme,
  colorFilter: colorFilter ??
  (color == null ? null : ColorFilter.mode(color, colorBlendMode)),
  clipBehavior: clipBehavior,

packages/core/lib/generators/integrations/svg_integration.dart

@@ -62,7 +62,7 @@ ${isPackage ? "\n static const String package = '$packageName';" : ''}
  return SvgPicture(
  _isVecFormat ? 
  AssetBytesLoader(_assetName, assetBundle: bundle, packageName: package) :
- SvgAssetLoader(_assetName, assetBundle: bundle, packageName: package),
+ SvgAssetLoader(_assetName, assetBundle: bundle, packageName: package, theme: theme),
  key: key,
  matchTextDirection: matchTextDirection,
  width: width,
@@ -73,7 +73,6 @@ ${isPackage ? "\n static const String package = '$packageName';" : ''}
  placeholderBuilder: placeholderBuilder,
  semanticsLabel: semanticsLabel,
  excludeFromSemantics: excludeFromSemantics,
- theme: theme,
  colorFilter: colorFilter ?? (color == null ? null : ColorFilter.mode(color, colorBlendMode)),
  clipBehavior: clipBehavior,
  cacheColorFilter: cacheColorFilter,