Improve Dev error details on extension validation

[isaacroldan]

WHY are these changes introduced?

Fixes #0000

WHAT is this pull request doing?

How to test your changes?

Post-release steps

Measuring impact

How do we know this change was effective? Please choose one:

• n/a - this doesn't need measurement, e.g. a linting rule or a bug-fix
• Existing analytics will cater for this addition
• PR includes analytics changes to measure impact

Checklist

• I've considered possible cross-platform impacts (Mac, Linux, Windows)
• I've considered possible documentation changes

[github-actions]

Coverage report

St.❔	Category	Percentage	Covered / Total
🟡	Statements	73.55% (-0.8% 🔻)	8421/11449
🟡	Branches	69.49% (-0.65% 🔻)	4102/5903
🟡	Functions	73.24% (-0.63% 🔻)	2217/3027
🟡	Lines	74.06% (-0.82% 🔻)	7962/10751

Show files with reduced coverage 🔻

St.❔	File	Statements	Branches	Functions	Lines
🟢	... / migrate-app-module.ts	89.19% (-0.28% 🔻)	85.71%	90.91%	91.18% (-0.25% 🔻)
🔴	... / dev-session.ts	3.54% (-0.72% 🔻)	0%	3.85% (-0.7% 🔻)	3.88% (-0.82% 🔻)
🔴	... / cli.ts	1.41% (-98.59% 🔻)	0% (-75% 🔻)	0% (-100% 🔻)	1.56% (-98.44% 🔻)
🔴	... / custom-oclif-loader.ts	0% (-28.13% 🔻)	0% (-11.9% 🔻)	0% (-33.33% 🔻)	0% (-28.13% 🔻)
🟡	... / error-handler.ts	66.33% (-10.2% 🔻)	68.52% (-9.26% 🔻)	57.14% (-14.29% 🔻)	66.67% (-10.42% 🔻)
🟡	... / error.ts	79.31% (-6.9% 🔻)	73.53% (-2.94% 🔻)	92.31% (-7.69% 🔻)	78.57% (-7.14% 🔻)
🟡	... / path.ts	73.33% (-3.33% 🔻)	72.22%	68.75% (-6.25% 🔻)	74.07% (-3.7% 🔻)
🔴	... / system.ts	33.33% (-1.55% 🔻)	21.43% (-1.9% 🔻)	62.5% (-4.17% 🔻)	34.29% (-1.43% 🔻)

Test suite run success

1925 tests passing in 875 suites.

Report generated by 🧪jest coverage report action from b6d9afb

[graphite-app]

forEach with async operations won't wait for all promises to resolve. Use Promise.all(errors.map()) to ensure all errors are processed before the function returns. This avoids potential race conditions and ensures proper error handling.

Spotted by Graphite Reviewer

Is this helpful? React 👍 or 👎 to let us know.