#3179: Viewers: Regression lines: additional correlation metrics with customization options

[LesiaPavlenko]

• Viewers: regression lines: additional correlation Metrics (the Mean Absolute error, Root Mean Squared Error) with ability to customize

R_ONE: y = 0+0x r2=NaN
S_ABS: y = 1+0x r2=NaN
S_ACHIR: y = 2+0*x r2=NaN

• Make Regression line splitting by colors configurable for categorical columns
  Currently, if a column is categorical and includes colors, the regression line automatically splits by color. Kristina has expressed interest in making this behavior configurable, allowing users to choose whether or not to split the regression line by colors.

[dnillovna]

This issue has been mirrored in Jira: https://reddata.atlassian.net/browse/GROK-17070