ls: fix leading space before first entry when color is enabled

[hz2]

Summary

• When --color is active and quoting is in use, entry names get wrapped in ANSI escape sequences. The alignment logic that prepends a space to unquoted entries was checking the raw first byte of the name, which is now an ESC character instead of a quote. This caused a spurious leading space on every output line in columnar mode.
• Added a helper that skips over ANSI CSI sequences before checking whether a name starts with a quote character, and used it in both the grid format and long format code paths.
• Added a regression test that asserts no leading space appears when all names are quoted and color is enabled.

Fixes #12432

Test plan

• Reproduced the bug using the exact steps from the issue (script + perl byte check)
• Verified output now matches GNU coreutils 9.9 byte for byte
• Confirmed the alignment space still works correctly for mixed quoted/unquoted names
• All 165 existing ls tests pass with no regressions
• New test covers the specific scenario from the issue

[github-actions]

GNU testsuite comparison:

Skip an intermittent issue tests/misc/io-errors (fails in this run but passes in the 'main' branch)
Skip an intermittent issue tests/tail/retry (fails in this run but passes in the 'main' branch)
Skip an intermittent issue tests/tail/tail-n0f (fails in this run but passes in the 'main' branch)
Skip an intermittent issue tests/timeout/timeout-group (fails in this run but passes in the 'main' branch)
Skipping an intermittent issue tests/tail/pid-pipe (passes in this run but fails in the 'main' branch)