Add GetLineBoundingRectangle API.

Add GetLineBoundingRectangle API.

Calculate the line size and position:
- X, the left starting point of the line.
- Y, the left top point of the line.
- Width.
- Height.

Function prototype: GetLineBoundingRectangle(ModelPtr model, uint32_t lineIndex);

Add new API to TextGeometry.

Reference patches:
https://review.tizen.org/gerrit/c/platform/core/uifw/dali-toolkit/+/266891

Change-Id: I742a44bd406bc13d1c3ec35bce3049b467d21962