FIX WebDav MacOS failed uploads php-fpm and big files (-36 error)

[gonzalo]

Current "SetEnvIf Transfer-Encoding "chunked" proxy-sendcl=1" setting fails with Macos Webdav Darwin client beacuse the header has a capital letter -> "Chunked" So you can fix it making condition case insensitive. Extended description and tests results on #48878

• Resolves: # [https://github.com/[Bug]: FIX for WebDav MacOS failed uploads with php-fpm and big files (-36 error) #48878]

Summary

Sorry if something is missing. This is my first PR.

TODO

• Nothing extra to do

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• (N/A) Tests (unit, integration, api and/or acceptance) are included
• (N/A) Screenshots before/after for front-end changes
• (N/A) Documentation (manuals or wiki) has been updated or is not required
• (N/A) Backports requested where applicable (ex: critical bugfixes)

[szaimen]

LGTM but didnt test

[welcome]

Thanks for your first pull request and welcome to the community! Feel free to keep them coming! If you are looking for issues to tackle then have a look at this selection: https://github.com/nextcloud/server/issues?q=is%3Aopen+is%3Aissue+label%3A%22good+first+issue%22

[szaimen]

/backport 0852dac to stable30