Update eslint-9 to flat config

[jalal246]

Waiting until airbnb config is fully migrated to flat config

[github-actions]

size-limit report 📦

Path	Size	Loading time (3g)	Running time (snapdragon)	Total time
packages/dflex-dnd/dist/dflex-dnd.mjs	10.88 KB (-9.34% 🔽)	218 ms (-9.34% 🔽)	87 ms (-75.23% 🔽)	305 ms
packages/dflex-core-instance/dist/dflex-core.mjs	58 B (-3.34% 🔽)	10 ms (0%)	6 ms (-81.45% 🔽)	16 ms
packages/dflex-dom-gen/dist/dflex-dom.mjs	26 B (+13.05% 🔺)	10 ms (0%)	2 ms (-92.67% 🔽)	12 ms
packages/dflex-store/dist/dflex-store.mjs	222 B (-8.27% 🔽)	10 ms (0%)	91 ms (+86.75% 🔺)	101 ms
packages/dflex-utils/dist/dflex-utils.mjs	238 B (-8.82% 🔽)	10 ms (0%)	4 ms (-93.63% 🔽)	14 ms
packages/dflex-draggable/dist/dflex-draggable.mjs	5.54 KB (-9.14% 🔽)	111 ms (-9.14% 🔽)	16 ms (-91.24% 🔽)	126 ms