Fix shutterstop

[stefanbode]

improved stop procedure to avoid overrun due to rounding issues between % and the real_position

Description:

Related issue (if applicable): fixes #10166

Checklist:

• [ x] The pull request is done against the latest dev branch
• [x ] Only relevant files were touched
• [ x] Only one feature/fix was added per PR and the code change compiles without warnings
• [ x] The code change is tested and works on Tasmota core ESP8266 V.2.7.4.9
• [ x] The code change is tested and works on Tasmota core ESP32 V.1.0.4.2
• [x ] I accept the CLA.

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