Revert "Pipeline operators: && and ||" (#7452)

Reverts nushell/nushell#7448

Some surprising behavior in how we do this. For example:

```
〉if (true || false) { print "yes!" } else { print "no!" }
no!
〉if (true or false) { print "yes!" } else { print "no!" }
yes!
```

This means for folks who are using the old `||`, they possibly get the
wrong answer once they upgrade. I don't think we can ship with that as
it will catch too many people by surprise and just make it easier to
write buggy code.

crates/nu-parser/src/parse_keywords.rs

@@ -1420,9 +1420,7 @@ pub fn parse_module_block(
 
                         pipeline
                     }
-                    LiteElement::Redirection(_, _, command) | LiteElement::Or(_, command) => {
-                        garbage_pipeline(&command.parts)
-                    }
+                    LiteElement::Redirection(_, _, command) => garbage_pipeline(&command.parts),
                 }
             } else {
                 error = Some(ParseError::Expected("not a pipeline".into(), span));