Generating index file breaks on special characters

[nwesthoff]

🐛 Bug Report

#332 fixed an issue generating component names with special characters. Though this fix does not seem to be used to generate export names in index files, which throws the following error:

> svgr-special-character-bug@1.0.0 build:icons ~/Git/svgr-special-character-bug
> svgr --out-dir icons -- svg

svg/Direction=Down.svg -> icons/Direction=down.js
~/Git/svgr-special-character-bug/node_modules/.pnpm/@svgr+cli@8.1.0/node_modules/@svgr/cli/dist/index.js:435
    throw error;
    ^

SyntaxError: Unexpected token, expected "," (1:30)
> 1 | export { default as Direction=down } from './Direction=down'

To Reproduce

1. Add an icon with special characters in the file name (I've tested = and →)
2. Run svgr cli svgr --out-dir icons -- svg (in repro pnpm build:icons), no special config
3. Generating the icon components works
4. Generating the index file fails

Expected behavior

I expect index files to use the same getComponentName function to generate the export name to avoid issues with special characters.

Link to repl or repo (highly encouraged)

GitHub Repro

System Info

## System:
 - OS: macOS 15.6
 - CPU: (12) arm64 Apple M2 Pro
 - Memory: 155.48 MB / 16.00 GB
 - Shell: 5.9 - /bin/zsh
## Binaries:
 - Node: 24.2.0 - /opt/homebrew/bin/node
 - Yarn: 1.22.22 - /opt/homebrew/bin/yarn
 - npm: 11.3.0 - /opt/homebrew/bin/npm
 - pnpm: 10.10.0 - ~/Library/pnpm/pnpm
 - bun: 1.1.43 - ~/.bun/bin/bun
## npmPackages:
 - @svgr/cli: ^8.1.0 => 8.1.0 
 - @svgr/core: ^8.1.0 => 8.1.0