Update 'restart connection' action to reset internal state (#19971)

## Summary of the Pull Request
I was becoming frustrated with getting in a state where a CLI app (i.e.
Copilot CLI) enters some VT state (like mouse mode) then doesn't unset
it when it accidentally exits. I normally use "Restart connection" to
keep the buffer and connect again. Problem is, "restart connection"
didn't actually reset the internal state! So I would type and get a
bunch of lingering VT escape sequences. This bug is tracked over in
#18425 in a more generic way.

This fixes that bug by doing the following:
- update `ITermDispatch::HardReset()` -->`HardReset(bool erase)`
   - `erase=true` does what `HardReset()` already did
- `erase=false` skips over clearing the screen and resetting the cursor
position
- expose `HardReset(false)` as `HardResetWithoutErase()` by piping it up
through `Terminal` --> `ControlCore` --> `TermControl`
-  update the restart connection handler
- `TerminalPage::_restartPaneConnection()` now calls
`HardResetWithoutErase()` before setting the new connection
- this is also the same route for the "Enter to restart connection"
scenario (text displayed when connection ends)

Relevant notes from PR discussion:
- `PSEUDOCONSOLE_INHERIT_CURSOR` is passed into the new connection via
`_restartPaneConnection()` --> `_duplicateConnectionForRestart()` -->
`_CreateConnectionFromSettings(profile,
*controlSettings.DefaultSettings(), true)`

## Validation Steps Performed
- Used this to enter mouse tracking mode: `Write-Host -NoNewline
"`e[?1003h`e[?1006h"`
- mouse selection doesn't work as usual (expected)
- invoke "restart connection" action
- mouse selection works as usual

Closes #18425