I have a problem with my chrome extension (made to accept automatically all the connection requests)

Question

I'd like to develop a Chrome extension that allows me to accept automatically all the connection requests on Linkledin, without any button, just by installing the extension.

My content.js is like this

chrome.runtime.onMessage.addListener(function(message, sender, sendResponse) {
    if (message.action === "addInvitations") {
        console.log("message?");
        addInvitations();
    }
});
  
function addInvitations() {
    console.log("la vie est belle");
    var connections = document.querySelectorAll('.invitation-card__action-btn.artdeco-button--secondary');
  
    for (var i = 0; i < connections.length; i++) {
      //connections[i].click();
      console.log("hep hep hep");
      console.log(connections[i]);

  }
}

and my background.js is like this :

chrome.runtime.onInstalled.addListener(function() {
    console.log("back ?");
    chrome.tabs.query({ url: "https://www.linkedin.com/mynetwork/invitation-manager/" }, function(tabs) {
      for (var i = 0; i < tabs.length; i++) {
        chrome.tabs.sendMessage(tabs[i].id, { action: "addInvitations" });
      }
    });
  });

But it does nothing !

On DevTools, there is no message beside the 4 console.log() i've put on the code. And on DevTools > Sources, there is no content.js when i'm on the right page.

console

My manifest is like this :

{
    "manifest_version": 2,
    "name": "LinkedIn Adder",
    "version": "1.0",
    "description": "Allows you to automatically accept connection requests on LinkedIn.",
    "icons": {
      "16": "add-user.png"
    },
    "background": {
      "scripts": ["background.js"]
    },
    "permissions": [
      "identity",
      "cookies",
      "activeTab"
    ],
    "browser_action": {
        "default_popup": "popup.html"
    },
    "content_scripts": [
      {
        "matches": ["https://www.linkedin.com/mynetwork/invitation-manager/"],
        "js": ["content.js"]
      }
    ]
  }

I can't see my problem, can anyone help?