fix: allow overriding Bearer token

[soedirgo]

When initializing SupabaseClient, if the Authorization header is provided, it will be used for _getAuthHeaders() instead of the session's access token or Supabase key.

[thorwebdev]

LGTM, thanks

[maxkostow]

This causes the Authorization header to be cached even after auth refreshes the access_token. This should probably clone the headers object before assigning the properties.

  private _getAuthHeaders(): GenericObject {
    const headers: GenericObject = { ...this.headers }
    const authBearer = this.auth.session()?.access_token ?? this.supabaseKey
    headers['apikey'] = this.supabaseKey
    headers['Authorization'] = headers['Authorization'] || `Bearer ${authBearer}`
    return headers
  }