Refactor which_package & which_prefix

[kenodegard]

Description

Consolidate which_package implementations and replaces legacy conda.models.dist.Dist usage with modern conda.models.records.PrefixRecords.

Discovered while working to remove usage of the following:

• linked_data_no_multichannels
• linked_data
• linked
• is_linked

Depends on #5055

Checklist - did you ...

• Add a file to the news directory (using the template) for the next release's release notes?
• Add / update necessary tests?
• Add / update outdated documentation?

[kenodegard]

linked_data_no_multichannels and linked_data do the following:

from conda.core.prefix_data import PrefixData
from conda.models.dist import Dist

def linked_data_no_multichannels(prefix):
    return {
        Dist.from_string(prec.fn, channel_override=prec.channel.name): prec
        for prec in PrefixData(prefix).iter_records()
    }


def linked_data(prefix):
    return {
        Dist(prec): prec
        for prec in PrefixData(prefix).iter_records()
    }

since this PR eliminates the poor PrefixRecord → Dist translation I don't believe there's a need to distinguish between avoid_canonical_channel_name anymore (not that I'm entirely sure what that means in the first place)