Fix undefined tpl vars in CiviReport

[colemanw]

Overview

Fixes a whole bunch of PHP notices on CiviReport screens.

[civibot]

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[demeritcowboy]

FYI some test fails:

api_v3_JobTest.testMailReportForPrint
CRM_Report_Utils_ReportTest.testOutputPrint

[colemanw]

Yea I left off an ! from an empty(). Glad the tests caught it.

I'm toying with the idea of using a mass regex replace to do simple transformations like {if $foo.bar} => {if !empty($foo.bar)}. It would result in a daunting PR but IMO is safer because a human doesn't have to write it.
It wouldn't be able to do the weird cases but could save us a lot of manual work for the simple ones.

[demeritcowboy]

I kind of agree with @eileenmcnaughton that some of these are pointing out places where something is missing that shouldn't be, maybe even some rogue typos, and so a mass replace with empty would hide those, but on the other hand it would be no different than it's been for years. So 🤷

[demeritcowboy]

jenkins retest this please

E2E\Core\AssetBuilderTest::testInvalid