You can use jsonlite::fromJSON to parse the JSON file
Example based on your JSON sample string
ss <- '[{"contributors": null, "truncated": false, "text": "RT @KazmiWajahat: Indian media including @CNNnews18 confirming Pakistans retaliation at LoC forward areas with heavy firing and shelling w\u2026", "is_quote_status": false}]'
library(jsonlite)
fromJSON(ss)
#  contributors truncated
#1           NA     FALSE
#                                                                                                                                       text
#1 RT @KazmiWajahat: Indian media including @CNNnews18 confirming Pakistans retaliation at LoC forward areas with heavy firing and shelling w…
#  is_quote_status
#1           FALSE
Here you end up with a data.frame consisting of only one row because of the minimal sample data you gave.
To take a slightly more complex example from the jsonlite vignette,
ss <-'[
    {"Name" : "Mario", "Age" : 32, "Occupation" : "Plumber"}, 
    {"Name" : "Peach", "Age" : 21, "Occupation" : "Princess"},
    {"Name" : "Bowser", "Occupation" : "Koopa"}]'
you can see how fromJSON parses the JSON string and returns a data.frame
fromJSON(ss)
#    Name Age Occupation
#1  Mario  32    Plumber
#2  Peach  21   Princess
#3 Bowser  NA      Koopa