test: remove deprecated getSnapshotSettings method (#28250)

Issue number: N/A

---------

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## What is the current behavior?
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The `getSnapshotSettings` method was used in the pre-generator test
infrastructure. It was deprecated at the start of the generator
migration.

## What is the new behavior?
<!-- Please describe the behavior or changes that are being added by
this PR. -->

- Now that the generator migration is complete, this method is no longer
needed. As a result, I removed it. Developers should use the
`screenshot` function:
https://github.com/ionic-team/ionic-framework/blob/main/core/src/utils/test/playwright/docs/api.md#using-the-return-value-from-each-configuration

## Does this introduce a breaking change?

- [ ] Yes
- [x] No

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and migration path for existing applications below. -->


## Other information

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screenshots of how the component looks before and after the change. -->

core/src/components/picker-column/test/test.utils.ts

@@ -39,7 +39,7 @@ export async function testPickerColumn(
     await page.waitForChanges();
 
     screenshots.push({
-      name: `picker-${description}-column-diff-${i}-${page.getSnapshotSettings()}.png`,
+      name: screenshot(`picker-${description}-column-diff-${i}`),
       screenshot: await page.screenshot(),
     });
   }