Remove useless title setter

sample/src/main/java/com/github/aachartmodel/aainfographics/demo/chartcomposer/CustomStyleChartComposer.kt

@@ -339,7 +339,6 @@ object CustomStyleChartComposer  {
 
         return AAChartModel()
             .chartType(AAChartType.Spline)
-            .title("")
             .backgroundColor("#4b2b7f")
             .yAxisTitle("")//设置Y轴标题
             .dataLabelsEnabled(false)//是否显示值
@@ -362,7 +361,6 @@ object CustomStyleChartComposer  {
 
         return AAChartModel()
             .chartType(AAChartType.Column)
-            .title("")
             .yAxisTitle("")//设置Y轴标题
             .dataLabelsEnabled(false)//是否显示值
             .tooltipEnabled(false)
@@ -387,7 +385,6 @@ object CustomStyleChartComposer  {
 
         return AAChartModel()
             .chartType(AAChartType.Area)
-            .title("")
             .yAxisTitle("")//设置Y轴标题
             .yAxisGridLineWidth(0f)
             .categories(arrayOf("Jan", "Feb", "Mar", "Apr", "May", "Jun", "July", "Aug", "Spe", "Oct", "Nov", "Dec"))

sample/src/main/java/com/github/aachartmodel/aainfographics/demo/chartcomposer/CustomTooltipComposer.kt

@@ -667,7 +667,6 @@ function () {
     fun customTooltipWhichDataSourceComeFromOutSideRatherThanSeries(): AAOptions {
         val aaChartModel = AAChartModel()
             .chartType(AAChartType.Column) //图表类型
-            .title("")
             .yAxisTitle("") //设置 Y 轴标题
             .yAxisLineWidth(1f) //Y轴轴线线宽为0即是隐藏Y轴轴线
             .yAxisGridLineWidth(1f) //y轴横向分割线宽度为1(为0即是隐藏分割线)