feat: use system locale for number formatting instead of setting (#64)

[Aga-C]

Type of change(s)

• Bug fix
• Feature / enhancement
• Infrastructure / tooling (CI, build, deps, tests)
• Documentation

What changed and why

• Used everywhere decimal and grouping separators taken from DecimalFormatSymbols.
• Removed the old setting for choosing what formatting user want (as it was invalid in some cases, as I described in App doesn't follow locale number formatting #64).

Before/After Screenshots/Screen Record

Fixes the following issue(s)

• Fixes App doesn't follow locale number formatting #64

Checklist

• I read the contribution guidelines.
• I manually tested my changes on device/emulator (if applicable).
• I updated the "Unreleased" section in CHANGELOG.md (if applicable).
• All checks are passing.

[naveensingh]

Updated lint and detekt configuration. The errors should go away once you merge main into this branch (or use the Update with rebase GitHub option).

[naveensingh]

Found two edge cases on locale change:

• History items use the previous formatting. For example, the result in 10,5 + 5 = 15,5 becomes 155 when switching from Polish to English. Previously, history was being cleared when the comma was toggled (not ideal either).
• The widget and the views still use the previous formatting.

Merging now, both of these can be handled later. Thank you.