standardized error diagram

[Yokozuna59]

• remove empty styles.js
• use named imports/exports instead of default
• remove unnecessary data in diagram definition

📑 Summary

Brief description about the content of your PR.

Resolves #

📏 Design Decisions

Describe the way your implementation works or what design decisions you made if applicable.

📋 Tasks

Make sure you

• 📖 have read the contribution guidelines
• 💻 have added necessary unit/e2e tests.
• 📓 have added documentation. Make sure MERMAID_RELEASE_VERSION is used for all new features.
• 🔖 targeted develop branch

[codecov]

Codecov Report

Merging #4718 (0d380bb) into develop (1078b1c) will decrease coverage by 0.02%.
The diff coverage is 20.00%.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #4718      +/-   ##
===========================================
- Coverage    46.07%   46.05%   -0.02%     
===========================================
  Files           53       53              
  Lines         6741     6733       -8     
  Branches        18       18              
===========================================
- Hits          3106     3101       -5     
+ Misses        3635     3632       -3     

Flag	Coverage Δ
unit	46.05% <20.00%> (-0.02%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files Changed	Coverage Δ
...ckages/mermaid/src/diagrams/error/errorRenderer.ts	20.98% <12.69%> (-5.02%)	⬇️
...ackages/mermaid/src/diagrams/error/errorDiagram.ts	86.66% <85.71%> (+12.75%)	⬆️

... and 1 file with indirect coverage changes