refactor: replace sort.Strings with slices.Sort (#23457)

The slices package provides type-safe generic replacements for the
old typed sort convenience functions. The codebase already uses
slices.Sort in 43 call sites; this finishes the migration for the
remaining 29.

- sort.Strings(x)          -> slices.Sort(x)
- sort.Float64s(x)         -> slices.Sort(x)
- sort.StringsAreSorted(x) -> slices.IsSorted(x)

coderd/notifications/notifications_test.go

@@ -18,7 +18,6 @@ import (
 	"path/filepath"
 	"regexp"
 	"slices"
-	"sort"
 	"strings"
 	"sync"
 	"testing"
@@ -549,8 +548,8 @@ func TestExpiredLeaseIsRequeued(t *testing.T) {
 		leasedIDs = append(leasedIDs, msg.ID.String())
 	}
 
-	sort.Strings(msgs)
-	sort.Strings(leasedIDs)
+	slices.Sort(msgs)
+	slices.Sort(leasedIDs)
 	require.EqualValues(t, msgs, leasedIDs)
 
 	// Wait out the lease period; all messages should be eligible to be re-acquired.