Update pester syntax to v4 (#11544)
* Capitalize 'Should' command and fix whitespace
```powershell
$_ -ireplace '\s?\|\s?should\b',' | Should'
```
* Capitalise and apply hyphen to 'Not' parameter
```powershell
$_ -ireplace '(\| Should) not\b','$1 -Not'
```
* Capitalise and apply hyphen to 'Be' parameter
```powershell
$_ -ireplace '(\| Should(?: -Not)?) -?be\b','$1 -Be'
```
* Capitalise and apply hyphen to 'BeExactly' parameter
$_ -ireplace '(\| Should(?: -Not)?) -?beexactly\b','$1 -BeExactly'
* Capitalise and apply hyphen to 'BeGreaterThan' parameter
```powershell
$_ -ireplace '(\| Should(?: -Not)?) -?begreaterthan\b','$1 -BeGreaterThan'
```
* Use 'BeTrue' parameter
```powershell
$_ -ireplace '(\| Should(?: -Not)?) -Be\s\$?true\b','$1 -BeTrue'
```
* Use 'BeFalse' parameter
```powershell
$_ -ireplace '(\| Should(?: -Not)?) -Be\s\$?false\b','$1 -BeFalse'
```
* Capitalise and apply hyphen to 'Match' parameter
```powershell
$_ -ireplace '(\| Should(?: -Not)?)\s-?match\b','$1 -Match'
```
* Capitalise and apply hyphen to 'Throw' parameter
```powershell
$_ -ireplace '(\| Should(?: -Not)?)\s-?throw\b','$1 -Throw'
```
* Capitalise and apply hyphen to 'BeNullOrEmpty' parameter
```powershell
$_ -ireplace '(\| Should(?: -Not)?)\s-?benullorempty\b','$1 -BeNullOrEmpty'
```
* Capitalise 'Because' parameter
```powershell
$_ -ireplace '\s-because\b',' -Because'
```
* Fix 'BeNullOrEmpty'
743983390e