New check for a custom Authorization header is case sensitive. Headers are case insensitive

[GaryAustin1]

Bug report

• [x ] I confirm this is a bug with Supabase, not with my own application.
• [ x] I confirm I have searched the Docs, GitHub Discussions, and Discord.

Describe the bug

The new code added 3 weeks ago is checking for an Authorization header. It looks for 'Authorization' in the header array. http headers are case insensitive.

Just worked on a user issue where they loaded the header in authorization = .... and then used the header option authorization in the global headers object.
This should work.

The change was here @kangmingtay
(https://github.com/supabase/supabase-js/blame/4dff472a15cb754bf9fa81af495a84b1f0c42b14/src/SupabaseClient.ts#L282)

To Reproduce

use

global: {
    headers: { 'authenticated': 'bearer myjwt' }

in createClient

Expected behavior

Case of header name should not matter.