fix(ui5-button): prioritize accessibleName over button text in aria-label (#12473)

When both text content and accessibleName are provided, the aria-label
should use only the accessibleName value plus button type text,
not concatenate both text content and accessibleName.

Fixes #12398

Author: unazko

packages/main/cypress/specs/Button.cy.tsx

@@ -348,6 +348,18 @@ describe("Accessibility", () => {
 			.should("have.attr", "aria-label", "Action Emphasized");
 	});
 
+	it("aria-label uses accessibleName when both text and accessibleName are provided", () => {
+		cy.mount(<Button design="Emphasized" accessibleName="Custom Action Label">Button Text</Button>);
+
+		cy.get("[ui5-button]")
+			.shadow()
+			.find("button")
+			.as("button");
+
+		cy.get("@button")
+			.should("have.attr", "aria-label", "Custom Action Label Emphasized");
+	});
+
 	it("aria-expanded is properly applied on the button tag", () => {
 		cy.mount(<Button icon="home" design="Emphasized">Action Bar Button</Button>);
 

packages/main/src/Button.ts

@@ -626,12 +626,14 @@ class Button extends UI5Element implements IButton {
 	}
 
 	get ariaLabelText() {
+		const effectiveAriaLabelText = getEffectiveAriaLabelText(this) || "";
 		const textContent = this.textContent || "";
-		const ariaLabelText = getEffectiveAriaLabelText(this) || "";
 		const typeLabelText = this.hasButtonType ? this.buttonTypeText : "";
 		const internalLabelText = this.effectiveBadgeDescriptionText || "";
 
-		const labelParts = [textContent, ariaLabelText, typeLabelText, internalLabelText].filter(part => part);
+		// Use either the effective aria label text (if accessibleName is provided) or the button's text content
+		const mainLabelText = effectiveAriaLabelText || textContent;
+		const labelParts = [mainLabelText, typeLabelText, internalLabelText].filter(part => part);
 		return labelParts.join(" ");
 	}