fix: Support up to 1e-20 numbers in ui.spinbox #1525

[marek-mihok]

The PR fulfills these requirements: (check all the apply)

• [x] It's submitted to the main branch.
• [x] When resolving a specific issue, it's referenced in the PR's title (e.g. feat: Add a button #xxx, where "xxx" is the issue number).
• [x] When resolving a specific issue, the PR description includes Closes #xxx, where "xxx" is the issue number.
• [x] If changes were made to ui folder, unit tests (make test) still pass.
• [x] New/updated tests are included

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The problem was with calculatePrecision function not working with scientific (exponential) notation numbers.

The fix converts scientific notation numbers to regular decimal numbers and it uses Number.toFixed() for conversion.

This solution is simple but works for numbers with up to 20 decimal points. To support more decimal points, it would need more complicated solution (something like this one but more reliable).

I think 20 decimal points should be enough for now and if it won't, someone will open the new issue. Wdyt @mturoci ?

Closes #1525

[mturoci]

I think 20 decimal points should be enough for now

wdyt @pascal-pfeiffer?

[pascal-pfeiffer]

20 decimals is enough for our needs. Sounds good! If there happens to be a new case that needs more, we can reconsider alternatives.

Thank you @marek-mihok !