Failed to generate dts with custom loader & manual type declaration

I'm trying to import svg files using text loader.

`tsup.config.ts`
```typescript
import { defineConfig } from 'tsup';
import { dependencies } from './package.json';

export default defineConfig({
entry: ['src/**/!(*.stories|*.test|*.d).(tsx|ts|jsx|js)'],
format: ['esm'],
target: 'esnext',
external: [
...Object.keys(dependencies),
],
loader: {
'.svg': 'text',
},
dts: true,
});

```

`src/assets/icons.ts`
```typescript
export { default as ascending } from './icons/ascending.svg';
export { default as barGraph } from './icons/barGraph.svg';
export { default as bookmarkOff } from './icons/bookmark-off.svg';
```

and then create a manual declaration file at the project root

`src/types.d.ts`
```typescript
declare module '*.svg' {
const src: string;
export default src;
}
```
It built well, but failed to generate d.ts with this error
```
RollupError: "default" is not exported by "src/assets/icons/ascending.svg", imported by "src/assets/icons.ts".
```

Start with tsup.config.ts and the dts: true path, then inspect how src/assets/icons.ts imports the SVG files and how src/types.d.ts is considered. Reproduce the build with the custom .svg text loader; done means declaration generation completes without the RollupError for the SVG default export.

Written by the indexing model from the issue text.