Fixed changeUIntScale for linearity when expanding range

[s-hadinger]

Description:

Fixed changeUIntScale to force linearity when expanding range, while keeping a bucket approximation when shortening range.

Checked that going from 0..100 -> 0..255 -> 0..100 ends with the same number as the origin. This is useful for dimmer/brightness conversion without drift.

Checklist:

• The pull request is done against the latest development branch
• Only relevant files were touched
• Only one feature/fix was added per PR and the code change compiles without warnings
• The code change is tested and works with Tasmota core ESP8266 V.2.7.4.9
• The code change is tested and works with Tasmota core ESP32 V.2.0.14
• I accept the CLA.

NOTE: The code change must pass CI tests. Your PR cannot be merged unless tests pass