[processing] Guard QGIS from crashing due to erroneous extent / invalid CRS in XYZ creation algorithms

[nirvn]

Description

Related to #60069 , this PR prevents QGIS from crashing when transforming erroneous bounding boxes within our pair of XYZ creation algorithms.

One thing I was wondering here is whether we should warn people if the WGS84 bounding box of their extent parameter results is a bounding box that goes beyond WGS84's limits. @nyalldawson , @m-kuhn , @alexbruy , thoughts?

[m-kuhn]

The fix is absolutely worth it

One thing I was wondering here is whether we should warn people if the WGS84 bounding box of their extent parameter results is a bounding box that goes beyond WGS84's limits. @nyalldawson , @m-kuhn , @alexbruy , thoughts?

Not sure in what scenario that would actually help someone

[alexbruy]

One thing I was wondering here is whether we should warn people if the WGS84 bounding box of their extent parameter results is a bounding box that goes beyond WGS84's limits.

I don't have a strong opinion here. I think that if someone selects incorrect extent/CRS such message won't be very helpful anyway.

[github-actions]

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