fix: update favorites only on mount

[nolanlawson]

Fixes #205

I can't really think of a strong reason to update the favorites immediately. The favorites are an enhancement; they aren't a critical part of the experience. And it's confusing to see them move around.

If people want these to update, they can create a new <emoji-picker> element or remove it from the DOM and re-insert it into the DOM. This seems reasonable to me as most pickers I imagine will be created on-demand and dismissed as soon as the user picks an emoji. If not, the favorites will update when the page is refreshed.

[github-actions]

📊 Tachometer Benchmark Results

Summary

benchmark-total

• emoji-picker-element-first-load: unsure 🔍 -7% - +8% (-6.78ms - +7.54ms)
  ^{this-change vs tip-of-tree}
• emoji-picker-element-second-load: unsure 🔍 -5% - +8% (-4.49ms - +8.22ms)
  ^{this-change vs tip-of-tree}

Results

emoji-picker-element-first-load

• Browser: chrome-headless 92.0.4515.131
• Sample size: 60
• Built by: Benchmarks #87

• Commit: 9f334fa

Version	Avg time	vs this-change	vs tip-of-tree tip-of-tree
this-change	89.75ms - 99.73ms	-	unsure 🔍 -7% - +8% -6.78ms - +7.54ms
tip-of-tree tip-of-tree	89.23ms - 99.50ms	unsure 🔍 -8% - +7% -7.54ms - +6.78ms	-

emoji-picker-element-second-load

• Browser: chrome-headless 92.0.4515.131
• Sample size: 50
• Built by: Benchmarks #87

• Commit: 9f334fa

Version	Avg time	vs this-change	vs tip-of-tree tip-of-tree
this-change	96.94ms - 105.14ms	-	unsure 🔍 -5% - +8% -4.49ms - +8.22ms
tip-of-tree tip-of-tree	94.32ms - 104.03ms	unsure 🔍 -8% - +4% -8.22ms - +4.49ms	-

_{tachometer-reporter-action v2 for Benchmarks}

[github-actions]

Size Change: -10 B (0%)

Total Size: 41.5 kB

Filename	Size	Change
./bundle.js	41.5 kB	-10 B (0%)

_{compressed-size-action}