文字の前にカンマを追加する

次のCSVファイルがあります。

"ADFS-Administrators","Administrator-Access","arn:aws:iam::279052847476:saml-provider/companyADFS"
"ADFS-amtest-ro","arn:aws:iam::279052847476:saml-provider/companyADFS"
"AWSAccCorpAdmin","arn:aws:iam::279052847476:saml-provider/LastPass"
"AWScompanyCorpAdmin","arn:aws:iam::279052847476:saml-provider/LastPass"
"AWScompanyCorpPowerUser","arn:aws:iam::279052847476:saml-provider/LastPass"
"flowlogsRole","oneClick_flowlogsRole_1495032428381",
"companyDevShutdownEC2Instaces","oneClick_lambda_basic_execution_1516271285849",
"companySAMLUser","arn:aws:iam::279052847476:saml-provider/companyAzureAD"
"lambda_stop_rundeck_instance","oneClick_lambda_basic_execution_1519651160794",
"OneLoginAdmin","arn:aws:iam::279052847476:saml-provider/OneLoginAdmin"
"OneLoginDev","arn:aws:iam::279052847476:saml-provider/OneLoginDev"
"vmimport","vmimport",
"workspaces_DefaultRole","SkyLightServiceAccess",

最初のカンマの後に次に始まる文字列がある場合は、各行に別のカンマを追加したいと思います。arn:aws:iam:

希望の出力（部分）：

"ADFS-amtest-ro",,"arn:aws:iam::279052847476:saml-provider/companyADFS"
"AWSAccCorpAdmin",,"arn:aws:iam::279052847476:saml-provider/LastPass"
"AWScompanyCorpAdmin",,"arn:aws:iam::279052847476:saml-provider/LastPass"
"AWScompanyCorpPowerUser",,"arn:aws:iam::279052847476:saml-provider/LastPass

文字列で始まらない行はarn:aws:iam何も変更しないでください。