Bug 210496 Add hasStyle property in reportItemModel extension point
When chart gets reportItem's properties by extending ReportItem, style properties are null. Hence, model needs to add hasStyle property in reportItemModel extension point
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/metadata/ElementDefn.java
* property definitions. The element definition (ElementDefn) defines the set of
 * properties available on that element.</dd>
 * 
 * <dt><strong>Property value </strong></dt>
 * <dd>A property value is the actual value that the user sets for a property.
 * A property value is associated with a element, and is stored in the
 * <code>DesignElement</code> class, or one of its subclasses. For
 * convenience, we often use the word "property" to mean a property value.
 * Property values can be in two states: set or unset. An unset value generally
 * causes the model to inherit the property value from the parent element (if
 * any). Properties in BIRT work much like properties in JavaScript objects.
 * </dd>
 * </dl>
 * 
 * <h3>System and User Properties</h3>
 * 
 * BIRT defines a wide range of element types, each with a wide range of
 * properties. Properties defined by BIRT itself are called
 * <em>system properties</em>. They are defined as part of the element type
 * definition in the meta-data file. System properties are of two types: normal
 * or <em>intrinsic</em>. An intrinsic property is one defined by a member
 * variable the DesignElement class or one of its subclasses. An normal property
 * is stored as a name/value pair in the DesignElement class.
 * <p>
 * BIRT also allows users to define their own properties. Such properties are
 * called, unsurprisingly, user properties. User properties are defined on an
 * element and are available to that element, and any elements that derive from
 * that element (see below.)
 * <p>
 * For the most part, system and user properties are defined in the same way as