Update Fuse Online Doc to clarify Conditional Flow section

related to https://issues.redhat.com/browse/ENTESB-17896

Clarify the Fuse Online doc here:
https://access.redhat.com/documentation/en-us/red_hat_fuse/7.10/html/integrating_applications_with_fuse_online/creating-integrations_ug#using-advanced-expression-builder_condition

specifically: this step 4i
In the initial When field, enter a Camel Simple Language conditional expression.

clarify that the The left hand side of the expression needs to be enclosed in ${...} . For example this will not work:
160 > ${body.pto}
bu this will work:
${body.pto} > 160

also mention these other examples provided by Zoran:
Provide a condition that you want to evaluate (for example, ${header.type} == 'note' or ${body.title} contains 'Important'). Note that the left hand side of the expression needs to be a variable expression enclosed in ${...}.