feat(Step Icon): Improve default option

[hirokiterashima]

Currently, we assign a gray hat icon for new steps and lessons. This makes the unit rather dull. This PR tries to improve this by making the unit more colorful and organized. We do this by changing the following:

• New lesson icon will have a random color, grid icon ("dashboard" material icon)
• New step icon will have the same color as the lesson, hat icon ("school" material icon)
  • This includes branch path steps and the merge step
• Imported step(s) icon(s) will have the same color as lesson they get imported into, same icon as before

Test

• Above works as described

Closes #2286

[qltysh]

Coverage Impact

Unable to calculate total coverage change because base branch coverage was not found.

Modified Files with Diff Coverage (5)

Rating	File	% Diff	Uncovered Line #s
	src/assets/wise5/services/authorBranchService.ts	100.0%
	src/assets/wise5/services/createBranchService.ts	100.0%
	src/assets/wise5/vle/node-icon/NodeIconColor.ts	50.0%	16
	src/assets/wise5/services/teacherProjectService.ts	100.0%
	...addNode/abstract-import-step/abstract-import-step.component.ts	16.7%	36-58
	Total	60.0%

🤖 Increase coverage with AI coding...

In the `issue-2286-step-icon-defaults` branch, add test coverage for this new code:

- `src/assets/wise5/authoringTool/addNode/abstract-import-step/abstract-import-step.component.ts` -- Line 36-58
- `src/assets/wise5/vle/node-icon/NodeIconColor.ts` -- Line 16

🚦 See full report on Qlty Cloud »

🛟 Help

• Diff Coverage: Coverage for added or modified lines of code (excludes deleted files). Learn more.

• Total Coverage: Coverage for the whole repository, calculated as the sum of all File Coverage. Learn more.

• File Coverage: Covered Lines divided by Covered Lines plus Missed Lines. (Excludes non-executable lines including blank lines and comments.)

  • Indirect Changes: Changes to File Coverage for files that were not modified in this PR. Learn more.