fix Response.redirect URL handling

[Monti-27]

Fixes #5301.

Response.redirect() was validating the input with a generic URI check and then writing the original string into the Location header. That meant absolute URLs were not serialized, and relative URLs like /foo were accepted.

This changes Response.redirect() to parse the target as a URL and store the serialized parsed URL in Location. It also enables the url dependency under the fetch feature so the non-default build stays correct.

Tests cover:

• serializing parsed absolute URLs
• preserving fragments
• rejecting relative redirect targets
• rejecting values that coerce to non-URL strings

Checks:

• cargo test -p boa_runtime response -- --nocapture
• cargo test -p boa_runtime --no-default-features --features fetch response_redirect -- --nocapture
• cargo clippy -p boa_runtime --all-features --all-targets -- -D warnings

[github-actions]

Test262 conformance changes

Test result	main count	PR count	difference
Total	53,125	53,125	0
Passed	50,827	50,827	0
Ignored	1,482	1,482	0
Failed	816	816	0
Panics	0	0	0
Conformance	95.67%	95.67%	0.00%

Tested main commit: f6021b3d3dd1249c9569be77f0ca9ccf00ea318a
Tested PR commit: 82718b65f21d67f40c109ffe2c51319723468d4c
Compare commits: f6021b3...82718b6

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 59.73%. Comparing base (6ddc2b4) to head (82718b6).
⚠️ Report is 929 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #5302       +/-   ##
===========================================
+ Coverage   47.24%   59.73%   +12.49%     
===========================================
  Files         476      589      +113     
  Lines       46892    63487    +16595     
===========================================
+ Hits        22154    37926    +15772     
- Misses      24738    25561      +823     

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[zhuzhu81998]

need adjusting (see comments in #5301. )
this should not throw.

[Monti-27]

yeah I'll push the commit by night was working on something else

[Monti-27]

I rechecked this more carefully. The spec parses against the current settings objects API base URL, so I think the /foo case depends on the host environment. that should explain why it works in your browser console ss while node and boa CLI both throw here

The part this PR is fixing is narrower: Location should use the serialized parsed url

@jedel1043 what do you think about keeping this PR scoped to that part ??