feat: support selectionMode="replace" in grid collection test utils

[LFDanLu]

Closes #7884

✅ Pull Request Checklist:

• Included link to corresponding React Spectrum GitHub Issue.
• Added/updated unit tests and storybook for this change (for new code or code which already has tests).
• Filled out test instructions.
• Updated documentation (if it already exists for this component).
• Looked at the Accessibility Practices for this feature - Aria Practices

📝 Test Instructions:

🧢 Your Project:

[rspbot]

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## API Changes

@react-aria/test-utils

/@react-aria/test-utils:triggerLongPress

 triggerLongPress {
   opts: {
     element: HTMLElement
-  advanceTimer: (number) => void | Promise<unknown>
+  advanceTimer: (number) => unknown | Promise<unknown>
   pointerOpts?: Record<string, any>
 }
   returnVal: undefined
 }

/@react-aria/test-utils:UserOpts

 UserOpts {
-  advanceTimer?: (number) => void | Promise<unknown>
+  advanceTimer?: (number) => unknown | Promise<unknown>
   interactionType?: 'mouse' | 'touch' | 'keyboard' = mouse
 }

---

@react-spectrum/test-utils

/@react-spectrum/test-utils:triggerLongPress

 triggerLongPress {
   opts: {
     element: HTMLElement
-  advanceTimer: (number) => void | Promise<unknown>
+  advanceTimer: (number) => unknown | Promise<unknown>
   pointerOpts?: Record<string, any>
 }
   returnVal: undefined
 }

/@react-spectrum/test-utils:UserOpts

 UserOpts {
-  advanceTimer?: (number) => void | Promise<unknown>
+  advanceTimer?: (number) => unknown | Promise<unknown>
   interactionType?: 'mouse' | 'touch' | 'keyboard' = mouse
 }

---

[LFDanLu]

This API naming feels unclear TBH, people may be confused as to when they would apply it. When set to selectionBehavior="replace" this causes the alt/meta key to be used when keyboard navigating/pressing to select a row so that it doesn't cause your previous selection to be replaced on focus/click. I wasn't certain if something like shouldUseModifierKeys was clear either since a user may not know what the "modifier keys" even do