fix: use scrollbar-gutter: stable

[nolanlawson]

Adapted from #427.

Uses scrollbar-gutter: stable so that the emoji don't shift around while searching. It's also a way simpler way to line up the favorites panel with the main grid.

Safari still doesn't support this, but it's behind a flag, and plus this is kind of a progressive enhancement, especially since the effect if you don't have it is just that the favorites panel doesn't line up nicely. Plus it only affects WebKit users who have perma-scrollbars enabled, which isn't the case for Safari on Mac or iOS or on Epiphany on Linux.

[github-actions]

📊 Tachometer Benchmark Results

Summary

benchmark-total

• emoji-picker-element-change-tab: slower ❌ 0% - 5% (0.09ms - 1.73ms)
  ^{this-change vs tip-of-tree}
• emoji-picker-element-database-interactions: unsure 🔍 -2% - +4% (-2.45ms - +4.40ms)
  ^{this-change vs tip-of-tree}
• emoji-picker-element-first-load: unsure 🔍 -4% - +4% (-1.76ms - +1.63ms)
  ^{this-change vs tip-of-tree}
• emoji-picker-element-search: unsure 🔍 -0% - +1% (-0.13ms - +0.28ms)
  ^{this-change vs tip-of-tree}
• emoji-picker-element-second-load: unsure 🔍 -7% - +4% (-2.40ms - +1.60ms)
  ^{this-change vs tip-of-tree}

Results

emoji-picker-element-change-tab

• Browser: chrome-headless 127.0.6533.72
• Sample size: 50
• Built by: Benchmarks #455

• Commit: f097c68

Version	Avg time	vs this-change	vs tip-of-tree tip-of-tree
this-change	34.30ms - 35.67ms	-	slower ❌ 0% - 5% 0.09ms - 1.73ms
tip-of-tree tip-of-tree	33.62ms - 34.53ms	faster ✔ 0% - 5% 0.09ms - 1.73ms	-

emoji-picker-element-database-interactions

• Browser: chrome-headless 127.0.6533.72
• Sample size: 50
• Built by: Benchmarks #455

• Commit: f097c68

Version	Avg time	vs this-change	vs tip-of-tree tip-of-tree
this-change	97.53ms - 102.49ms	-	unsure 🔍 -2% - +4% -2.45ms - +4.40ms
tip-of-tree tip-of-tree	96.67ms - 101.40ms	unsure 🔍 -4% - +2% -4.40ms - +2.45ms	-

emoji-picker-element-first-load

• Browser: chrome-headless 127.0.6533.72
• Sample size: 50
• Built by: Benchmarks #455

• Commit: f097c68

Version	Avg time	vs this-change	vs tip-of-tree tip-of-tree
this-change	44.76ms - 47.53ms	-	unsure 🔍 -4% - +4% -1.76ms - +1.63ms
tip-of-tree tip-of-tree	45.23ms - 47.19ms	unsure 🔍 -4% - +4% -1.63ms - +1.76ms	-

emoji-picker-element-search

• Browser: chrome-headless 127.0.6533.72
• Sample size: 50
• Built by: Benchmarks #455

• Commit: f097c68

Version	Avg time	vs this-change	vs tip-of-tree tip-of-tree
this-change	49.76ms - 50.08ms	-	unsure 🔍 -0% - +1% -0.13ms - +0.28ms
tip-of-tree tip-of-tree	49.72ms - 49.97ms	unsure 🔍 -1% - +0% -0.28ms - +0.13ms	-

emoji-picker-element-second-load

• Browser: chrome-headless 127.0.6533.72
• Sample size: 50
• Built by: Benchmarks #455

• Commit: f097c68

Version	Avg time	vs this-change	vs tip-of-tree tip-of-tree
this-change	33.64ms - 36.44ms	-	unsure 🔍 -7% - +4% -2.40ms - +1.60ms
tip-of-tree tip-of-tree	34.00ms - 36.87ms	unsure 🔍 -5% - +7% -1.60ms - +2.40ms	-

_{tachometer-reporter-action v2 for Benchmarks}

[github-actions]

Size Change: -143 B (-0.39%)

Total Size: 36.3 kB

Filename	Size	Change
./bundle.js	36.3 kB	-143 B (-0.39%)

_{compressed-size-action}