yazi: add icon theming for v26.1.22

[kerfuzzle]

• Manually specified icon colours as the default was changed to blue in sxyazi/yazi@41e5717
• Update nixpkgs flake input so that it has yazi v26.1.22

Fixes #2165.

Currently, I have just chosen colours from the base16 scheme that were similar to those in https://github.com/sxyazi/yazi/blob/main/yazi-config/preset/theme-dark.toml. Let me know if you think that they should be changed.

The testbed still seems to be having the issue where the instance launched on startup has an error but opening a second instance in a new terminal fixes this.

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• I certify that I have the right to submit this contribution under the MIT license
• Commit messages adhere to Stylix commit conventions
• Theming changes adhere to the Stylix style guide
• Changes have been tested locally
• Changes have been tested in testbeds
• Each commit in this PR is suitable for backport to the current stable branch

[trueNAHO]

Fixes #2165.

Thanks for fixing this.

Currently, I have just chosen colours from the base16 scheme that were similar to those in https://github.com/sxyazi/yazi/blob/main/yazi-config/preset/theme-dark.toml. Let me know if you think that they should be changed.

LGTM.

• Update nixpkgs flake input so that it has yazi v26.1.22

This PR should be merged after #2159 because it also updates the Nixpkgs input to the same revision, but fails due to upstream errors.

The testbed still seems to be having the issue where the instance launched on startup has an error but opening a second instance in a new terminal fixes this.

This has not been worked on since: #1731. Feel free to fix this in a separate PR.