[DOCS] `cqlsh exec` example given in docs triggers deprecation

The example given by the CLI for executing cql inline omits the -e flag before the CQL statement, which is deprecated.

This is seen on version 1.0.2 of the CLI. The help message comes from running astra db cqlsh --help.

Image

Proposed solution

add the -e flag to the example to prevent the deprecation warning.