fix: calculate encoded lengths from view byte lengths

[bensynapse]

I run Live Tennis API.

What is the purpose of this pull request? (put an "X" next to item)

[ ] Documentation update
[X] Bug fix
[ ] New feature
[ ] Other, please explain:

What changes did you make? (Give an overview)

encodingLength() uses the view's byteLength directly. A three byte view at offset 20 previously reported -13 encoded bytes. It now reports 5, matching encode().

The tests cover typed arrays, DataView and Buffer slices, including empty views and nested containers. A preallocation test reproduces the resulting RangeError before the fix.

Which issue (if any) does this pull request address?

No existing issue.

Is there anything you'd like reviewers to focus on?

A view's byteLength already excludes bytes before its offset.

node node_modules/tape/bin/tape test/encoding-length.test.js passes all 39 assertions on Node 12.22.12 and 22.23.2. Standard passes on both versions.

npm test stops in decode.dictionary with a TextDecoder argument error on both versions. The same failure reproduces on unchanged master with uint8-util 2.3.2.