[ty] Fix precedence of `all` selector in TOML configurations (#23723)
## Summary
Closes https://github.com/astral-sh/ty/issues/2952.
TOML tables are unordered — the spec says key/value pairs within tables
are not guaranteed to be in any specific order. However, the `toml`
crate happens to sort keys lexicographically when deserializing. This
means that rules like `abstract-method-in-final-class` sort *before*
`all`, so the `all` selector silently overrides the more-specific rule
when processed sequentially.
This PR fixes the issue by sorting selectors from the same configuration
file so that `all` is always applied first, then specific per-rule
selectors are applied afterwards. This ensures that specific rules
always take precedence over `all` within a given config file, regardless
of lexicographic ordering.
The fix is scoped to file-based configuration only — CLI argument order
is still preserved as-is, since users have explicit control over
ordering there.
## Test plan
Added a test (`configuration_all_rules_with_rule_sorting_before_all`)
that uses `abstract-method-in-final-class` (which sorts before `all`) to
verify the specific rule takes precedence.