Fix(webapp): Show an error to the user when their add-on upgrade payment fails #4476

Job	Run time
sdk-compat / Bun Runtime	1m 57s
sdk-compat / Node.js 22.12 (ubuntu-latest)	2m 0s
e2e / 🧪 CLI v3 tests (windows-latest - pnpm)	3m 47s
e2e / 🧪 CLI v3 tests (ubuntu-latest - npm)	1m 44s
sdk-compat / Cloudflare Workers	2m 6s
units / packages / 🧪 Unit Tests: Packages (1, 1)	7m 30s
sdk-compat / Deno Runtime	2m 1s
units / internal / 🧪 Unit Tests: Internal (8, 8)	3m 27s
typecheck / typecheck	6m 43s
e2e / 🧪 CLI v3 tests (ubuntu-latest - pnpm)	1m 43s
units / webapp / 🧪 Unit Tests: Webapp (6, 8)	3m 55s
units / internal / 🧪 Unit Tests: Internal (1, 8)	5m 20s
units / internal / 🧪 Unit Tests: Internal (6, 8)	4m 37s
sdk-compat / Node.js 20.20 (ubuntu-latest)	1m 57s
units / internal / 🧪 Unit Tests: Internal (5, 8)	3m 49s
units / internal / 🧪 Unit Tests: Internal (4, 8)	5m 17s
units / internal / 🧪 Unit Tests: Internal (2, 8)	5m 20s
units / webapp / 🧪 Unit Tests: Webapp (3, 8)	3m 12s
units / webapp / 🧪 Unit Tests: Webapp (2, 8)	4m 7s
units / webapp / 🧪 Unit Tests: Webapp (7, 8)	5m 47s
units / internal / 🧪 Unit Tests: Internal (7, 8)	5m 3s
units / webapp / 🧪 Unit Tests: Webapp (5, 8)	7m 29s
units / webapp / 🧪 Unit Tests: Webapp (1, 8)	6m 3s
units / webapp / 🧪 Unit Tests: Webapp (4, 8)	5m 46s
e2e / 🧪 CLI v3 tests (windows-latest - npm)	3m 12s
units / internal / 🧪 Unit Tests: Internal (3, 8)	5m 19s
units / webapp / 🧪 Unit Tests: Webapp (8, 8)	2m 40s
units / internal / 📊 Merge Reports	17s
units / webapp / 📊 Merge Reports	1s
units / packages / 📊 Merge Reports	1s
	1h 52m 10s

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