[ISSUE][DOCS] Multiple Spline documentation page issues

[LB-ArturZieba]

Describe the issue

There are multiple issues with the Spline documentation page, they will be listed here along with Expected experience wherever appropriate:

1. It is stated in the description that "The Spline component creates a line that is 4 meters long, with 4 points.", while when compared to the Box Shape component which is 1x1x1m, it appears to be 8m long. Expected: The description is changed to reflect how Spline component appears in the Editor.

2. "Base properties" section name is not like "White Box properties" on https://o3de.org/docs/user-guide/components/reference/shape/white-box/. Expected: "Properties" section is named "Spline properties".

3. "Base properties table" - Spline Default is blank. Expected: Spline Default should be "Linear Spline".

4. "Base properties table" - Spline Values are: Linear, Bezier, Catmull-Rom. Expected: Spline Values should be Linear Spline, Bezier Spline, and Catmull Rom Spline as they appear in engine and screenshots attached on the page.

5. "Edit Mode actions" - Select multiple does not require the Shift key to be held when selecting multiple vertices. Expected: The information about holding Shift when selecting multiple vertices is not present in the "Edit Mode actions".

6. "SplineComponentRequestBus" section mentions BoxShapeComponentRequestBus in the description. Expected: BoxShapeComponentRequestBus should be changed to SplineComponentRequestBus.

7. "SplineComponentRequestBus" section refrences SplineComponentRequestBus, while there are currently no SplineComponentRequestBus Script Canvas nodes, nor any other nodes referencing Spline component available. It should also be noted that there are no VertexContainer nodes present.

Impacted page(s)

https://o3de.org/docs/user-guide/components/reference/shape/spline/

[LB-ArturZieba]

Issues verified as fixed.