feat: enhanced delegation enforcement checks

[krpeacock]

Description

So far, the JavaScript agent has not enforced checks around delegation constraints. This meant that developers had to encounter errors later in the development process, often with less helpful certificate errors.

These changes introduce the following constraints, which now throw errors during the creation of a delegation chain:

• Expiration
• Max number of targets
• Max delegation chain length
• No longer allows repeats of public keys in the chain

This complies with the constraints indicated in the Internet Computer Interface Specification

Fixes # (issue)

How Has This Been Tested?

New and updated unit tests

Checklist:

• My changes follow the guidelines in CONTRIBUTING.md.
• The title of this PR complies with Conventional Commits.
• I have edited the CHANGELOG accordingly.
• I have made corresponding changes to the documentation.

[github-actions]

size-limit report 📦

Path	Size
@dfinity/agent	87.38 KB (0%)
@dfinity/candid	13.52 KB (0%)
@dfinity/principal	5.15 KB (0%)
@dfinity/auth-client	92.83 KB (+0.32% 🔺)
@dfinity/assets	89.96 KB (0%)
@dfinity/identity	90.12 KB (+0.35% 🔺)
@dfinity/identity-secp256k1	232.51 KB (0%)

[ericswanson-dfinity]

for (it in collection) {
    do something with it
}

is easier to understand than

let current = something else;
for (it in collection) {
    do something with current
    current = it
}
now check current for something // last value in collection

[krpeacock]

for (it in collection) {
    do something with it
}

is easier to understand than

let current = something else;
for (it in collection) {
    do something with current
    current = it
}
now check current for something // last value in collection

Valid point! I've refactored to use a reduce function which is more semantically appropriate

[ericswanson-dfinity]

Given that options.previous is a DelegationChain, is it really necessary to check that options.previous.delegations has no repeated delegations?

Asked another way, does DelegationChain have an invariant that delegations has no repeated public keys?

If so, it should be sufficient (and simpler) here to check that to is not found among options.previous.delegations.

[krpeacock]

If TypeScript was the runtime language of the web, we could be confident that the other chain is a valid DelegationChain. However, if we want runtime validation, we have to do the checks ourself

[ericswanson-dfinity]

good thing MAXIMUM_DELEGATION_CHAIN_LENGTH is only 20. Pretty sure this is O(n^2) or possibly O(n^2 log n).