[META] Data Explorer fixes

[wbeckler]

The following issues address UI regressions in the Data Explorer experience that were introduced in 2.9, 2.10 or 2.11

Fixes for 2.12 (maybe should be back ported to 2.11)

• [BUG] Changing from a search with few results to a search with more results keeps the number of rows from the previous search #5659
• [BUG] [Discover] Missing field in index pattern throws whole page error #5625
• [BUG] Copying data from columns in discover includes extra data #5570
• [BUG] Filtering index pattern in Discover page does not work #5604
• [BUG][Discover] "_source" Not Added to Side Nav on Removing All Columns with doc_table:hideTimeColumn Enabled #5538
• [BUG][Disocver] Timefield of an indexPattern would get added to selected field in the side nav when removing a column from the canvas #5527
• [BUG][Discover] Discover table panel won't adjust the size automatically when time range changes #5440
• [BUG]match_all query filters applied despite courier:ignoreFilterIfFieldNotInIndex setting enabled #5423
• [BUG] No line wrapping when displaying fields (dashboard v 2.11) #5404
• [BUG]Discover: Some Fields Aren't Displayed in the Left Navigation Bar #5400
• [BUG] [Data Explorer] Modify columns on switch #5268
• [BUG] Discover - 'truncate:maxHeight' no longer working 2.10.0 #5227
• [BUG] slide drawer navigation item 'Discover' doesn't have active background when selected #5226
• [BUG] Multiline content in [message] field is not displayed correctly  #5208

NOTE: There is a separate Data Explorer issue that covers the effort to restore the pre-2.11 version of Data Explorer:
#5714

[ananzh]

Checked issues all have fixes. We are asking customers' thoughts on the fixes.

[wbeckler]

I closed the ones where fixes are merged. If the poster wants to reopen we can do that with updated details that we'll address in a subsequent release.