Fix calculator search precision and rounding errors

[tgex0]

Description

Fixes calculator search result precision and rounding errors.

Previously:

• pi*0 = 0E-15
• pi*1.000 = 3.141592653589793000
• 2.0*6.0 = 6.00
• 1/3*3 = 0.9999999999999999

This PR fixes such issues, now resulting in:

• pi*0 = 0
• pi*1.000 = 3.141592653589793
• 2.0*6.0 = 6
• 1/3*3 = 1

Fixes #4756

Type of change

❌ General change (non-breaking change that doesn't fit the below categories like copyediting)
✅ Bug fix (non-breaking change which fixes an issue)
❌ New feature (non-breaking change which adds functionality)
❌ Breaking change (fix or feature that would cause existing functionality to not work as expected)

[tgex0]

I changed this PR to a draft to fix a further problem that was revealed by my initial fix.

a527e91 was added to ensure that the equation displayed in the search result tile always reflects the actual search typed in by the user.

The content of the tile (the result and the equation) is only updated if the result or the id changes. (The id uses the result so if the result does not change, the id will not change either.)
Previously, if a user typed in 3*1.0 and then added another zero, the result would change (to 3.100) so the tile was updated and the problem was not evident.

After my initial commit 41ab80a, the result no longer shows insignificant trailing zeros so the result does not change (from 3*1.0 to 3*1.00, for example) and, thus, the tile is not updated if the user adds insignificant zeros to the search.

If the user were to type in 3*1.00001, the equation in the tile would not be updated with all the zeros until the final 1 was entered.

Without changing the logic of when the tile should be updated, the easiest solution is to change the id (with a random value on each search input change), as the result itself cannot be changed.