fix #7440 feat(nimbus): migrate sticky targeting configs

[jaredlockhart]

Because

• Now that the sticky targeting clause is moved right into the NimbusExperiment targeting method
• There's no need for the sticky clause to be included in individual targeting configs

This commit

• Removes the sticky clauses from all desktop and mobile targeting configs
• Removes the now redundant 'pip_never_used_sticky' targeting config and migrates experiments that used it to 'pip_never_used'
• Migrates all existing experiments that use a previously sticky targeting config to have is_sticky=True
• Discovered that some JEXL clauses were not being evaluated at all as part of the integration tests becuase of short circuiting behaviour in the JEXL evaluator
• Reworked the SDK integration test to pass values in as their expected types rather than as strings which was triggering a suppressed error about comparing strings to integers
• Filed Invalid variables in left hand of JEXL or expression are not evaluated #7449 as a followup

[b4handjr]

why is this changed?

[jaredlockhart]

Oh vscode moved the indentation around

[jaredlockhart]

The actual change was trying to get the custom_targeting_attributes to have the expected types, ie integers and bools, rather than strings. But it turns out this whole thing gets parsed and expects only string types. But you can pass in custom_targeting_attributes separately into the helper encoded as JSON with the actual types, so I ended up just taking it out of here entirely.

[yashika-khurana]

LGTM! 🚀

[dmose]

The desktop sticky migration stuff looks good to me. r=dmose