View() does play well with dplyr group_by()

Describe the bug
Using dplyr::group_by on a dataset will break the View() function in the Session Watcher

To Reproduce

1. library(dplyr)
2. Reproduce the error

mtcars %>% group_by(cyl) %>% View()
Error: Argument 3 must be length 32, not 1

3. Workaround

mtcars %>% group_by(cyl) %>% ungroup() %>% View()

setting.json

    "r.alwaysUseActiveTerminal": true,
    "r.bracketedPaste": true,
    "r.rterm.mac": "/usr/local/bin/radian"
    "r.sessionWatcher": true

Expected behavior
The view function should not crash with group_by and could possibly also display the groups as in print.tibble()

Environment:

• OS: macOS
• VSCode Version: 1.42.1
• R Version: 3.6.2
• vscode-R version: 1.2.6

[renkun-ken]

I could reproduce it with the following backtrace:

> mtcars %>% group_by(cyl) %>% View()                                                                        
Error: Argument 3 must be length 32, not 1
Backtrace:
1: stop(list(message = "Argument 3 must be length 32, not 1", call = NULL, 
    cppstack = NULL))
2: cbind_all(x)
3: bind_cols(...)
4: cbind(deparse.level, ...)
5: data <- cbind(" " = rownames, data, stringsAsFactors = FALSE)
6: data <- dataview_table(x)
7: View(.)
8: function_list[[k]](value)
9: withVisible(function_list[[k]](value))
10: freduce(value, `_function_list`)
11: `_fseq`(`_lhs`)
12: eval(quote(`_fseq`(`_lhs`)), env, env)
13: eval(quote(`_fseq`(`_lhs`)), env, env)
14: withVisible(eval(quote(`_fseq`(`_lhs`)), env, env))
15: mtcars %>% group_by(cyl) %>% View()

I need to take a closer look at dataview_table where grouped_df seems to mess up cbind in the function.