fix(blazorui): resolve custom ChevronDownIcon issue in BitNav #10189 (#10190)

Author: Cyrus-Sushiant

src/BlazorUI/Bit.BlazorUI/Components/Navs/Nav/_BitNavChild.razor

@@ -64,7 +64,7 @@
                     {
                         <div class="bit-nav-itg">
                             <div class="bit-nav-iit" style="@(Nav.ReversedChevron ? "flex-flow:row-reverse" : null)">
-                                <i class="bit-icon bit-icon--@(Nav.ChevronDownIcon ?? "ChevronRight") @(Nav.ChevronDownIcon.HasNoValue() && isExpanded ? "bit-nav-exp" : "bit-ico-r90")" aria-hidden="true" />
+                                <i class="bit-icon bit-icon--@(Nav.ChevronDownIcon ?? "ChevronRight") @(Nav.ChevronDownIcon.HasValue() ? "" : (isExpanded ? "bit-nav-exp" : "bit-ico-r90"))" aria-hidden="true" />
                                 <span class="bit-nav-ghd">@text</span>
                             </div>
                             <div title="@description"
@@ -77,7 +77,7 @@
                     else
                     {
                         <div class="bit-nav-iit" style="@(Nav.ReversedChevron ? "flex-flow:row-reverse" : null)">
-                            <i class="bit-icon bit-icon--@(Nav.ChevronDownIcon ?? "ChevronRight") @(Nav.ChevronDownIcon.HasNoValue() && isExpanded ? "bit-nav-exp" : "bit-ico-r90")" aria-hidden="true" />
+                            <i class="bit-icon bit-icon--@(Nav.ChevronDownIcon ?? "ChevronRight") @(Nav.ChevronDownIcon.HasValue() ? "" : (isExpanded ? "bit-nav-exp" : "bit-ico-r90"))" aria-hidden="true" />
                             <span class="bit-nav-ghd">@text</span>
                         </div>
                     }
@@ -139,7 +139,7 @@
                                  class="bit-nav-cbt @Nav.Classes?.ToggleButton"
                                  aria-expanded="@(isExpanded ? "true" : "false")"
                                  aria-label="@(isExpanded ? colAriaLabel : expAriaLabel)">
-                                <i class="bit-icon bit-icon--@(Nav.ChevronDownIcon ?? "ChevronRight") @(Nav.ChevronDownIcon.HasNoValue() && isExpanded ? "bit-nav-exp" : "bit-ico-r90")" aria-hidden="true" />
+                                <i class="bit-icon bit-icon--@(Nav.ChevronDownIcon ?? "ChevronRight") @(Nav.ChevronDownIcon.HasValue() ? "" : (isExpanded ? "bit-nav-exp" : "bit-ico-r90"))" aria-hidden="true" />
                             </div>
                         }
                         <div style="@GetItemStyles()"