fix(segment): setting value via binding updates button state (#28837)

Issue number: resolves #28816 --------- <!-- Please do not submit updates to dependencies unless it fixes an issue. --> <!-- Please try to limit your pull request to one type (bugfix, feature, etc). Submit multiple pull requests if needed. --> ## What is the current behavior? <!-- Please describe the current behavior that you are modifying. --> The value is set on Segment asynchronously when binding it in Angular. However, the timing works out such that the value changes after `connectedCallback` is fired but before any Stencil Watchers are configured. As a result, our `value` property watcher does not fire which causes `ionSelect` to not be emitted. Segment Buttons rely on this event to know when to update their state (if the value changes such that a segment button is now selected). This results in a checked segment button not appearing checked. This is similar to other issues that have been fixed: #28510 #28488 #28526 ## What is the new behavior? <!-- Please describe the behavior or changes that are being added by this PR. --> - Segment now emits `ionSelect` on `componentDidLoad` so that any descendant segment buttons can update correctly. ## Does this introduce a breaking change? - [ ] Yes - [x] No <!-- If this introduces a breaking change: 1. Describe the impact and migration path for existing applications below. 2. Update the BREAKING.md file with the breaking change. 3. Add "BREAKING CHANGE: [...]" to the commit description when merging. See https://github.com/ionic-team/ionic-framework/blob/main/.github/CONTRIBUTING.md#footer for more information. --> ## Other information <!-- Any other information that is important to this PR such as screenshots of how the component looks before and after the change. --> Dev build: `7.6.5-dev.11705415448.16878103` This is a timing issue with Stencil, so I am unable to write a reliable automated test. Reviewers should test the dev build in the repro provided in the linked issue.

Author: liamdebeasi

core/src/components/segment/segment.tsx

@@ -140,6 +140,14 @@ export class Segment implements ComponentInterface {
  async componentDidLoad() {
  this.setCheckedClasses();
 
+ /**
+ * If the value changes before watchers
+ * are setup, then the ionSelect watch callback
+ * will not fire. As a result, we manually
+ * fire this event when Select is loaded.
+ */
+ this.ionSelect.emit({ value: this.value });
+
  /**
  * We need to wait for the buttons to all be rendered
  * before we can scroll.