[Bug]: Coachmark step count is not localized

### Code of conduct

- [X] I agree to follow this project's code of conduct.

### Impacted component(s)

Coachmark

### Expected behavior

In the Coachmark component the step count, for example "1 of 3" has hardcoded the "of" string. The expected behavior is that this string is localized, or is at least configurable so the client can pass in the string to use in this case.

### Actual behavior

The "of" word is hardcoded.

### Screenshots


### What browsers are you seeing the problem in?

Chrome

### How can we reproduce this issue?

Bug was discovered in a pre-release version so I can't share my own reproduction steps, as the feature has not been publicly released. But this surely reproduces anywhere Coachmark component is used.
1. Change language to non-english
2. Enter multi-step coachmark tour
Code where this is hard-coded is here https://github.com/adobe/spectrum-web-components/blob/a2b6bea7142930d8143d9ca887e2c56ffa71a669/packages/coachmark/src/Coachmark.ts#L278

### Sample code or abstract reproduction which illustrates the problem

_No response_

### Severity

SEV 3

### Logs taken while reproducing problem

_No response_

Start in packages/coachmark/src/Coachmark.ts around line 278, where the step count is assembled. Check the Coachmark usage and localization behavior with a non-English multi-step tour; done means the “of” text is localized or can be supplied by the client.

Written by the indexing model from the issue text.