Add support for HTTPS redirect URLs [SDK-4754]

[X] All new/changed/fixed functionality is covered by tests (or N/A)
[ ] I have added documentation for all new/changed functionality (or N/A) -> docs will be added in a follow up PR.

📋 Changes

This PR updates Auth0.swift to v2.6.0, and adds a new configuration option to opt into using HTTPS redirect URLs when performing web-based authentication.

🎯 Testing

Besides adding unit tests, the changes were tested manually with Xcode 15.3 (15E204a), on iOS 17.4 and 17.2, and macOS 14.4 and 14.3.1.

iOS 17.4 simulator

https://github.com/auth0/auth0-flutter/assets/5055789/e6245b88-a77f-43e2-8ad0-3d47f1d2317f

iOS 17.2 simulator

https://github.com/auth0/auth0-flutter/assets/5055789/2f74c738-52b0-4e86-aec0-f83e1a91246e

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 96.34%. Comparing base (253209a) to head (dd43ce6). Report is 41 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #417 +/- ## ============================================ + Coverage 96.08% 96.34% +0.25% ============================================ Files 97 98 +1 Lines 1611 1613 +2 Branches 331 348 +17 ============================================ + Hits 1548 1554 +6 - Misses 49 50 +1 + Partials 14 9 -5 ``` | [Flag](https://app.codecov.io/gh/auth0/auth0-flutter/pull/417/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=auth0) | Coverage Δ | | |---|---|---| | [auth0_flutter](https://app.codecov.io/gh/auth0/auth0-flutter/pull/417/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=auth0) | `100.00% <100.00%> (ø)` | | | [auth0_flutter_android](https://app.codecov.io/gh/auth0/auth0-flutter/pull/417/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=auth0) | `97.35% <ø> (+0.79%)` | :arrow_up: | | [auth0_flutter_ios](https://app.codecov.io/gh/auth0/auth0-flutter/pull/417/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=auth0) | `99.70% <100.00%> (-0.14%)` | :arrow_down: | | [auth0_flutter_platform_interface](https://app.codecov.io/gh/auth0/auth0-flutter/pull/417/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=auth0) | `87.06% <100.00%> (+0.03%)` | :arrow_up: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=auth0#carryforward-flags-in-the-pull-request-comment) to find out more.

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auth0 / auth0-flutter