Feat: hide blocks not challenges (#39504)

* fix: remove isHidden flag from frontmatter

* fix: add isUpcomingChange

Co-authored-by: Ahmad Abdolsaheb <ahmad.abdolsaheb@gmail.com>

* feat: hide blocks not challenges

Co-authored-by: Ahmad Abdolsaheb <ahmad.abdolsaheb@gmail.com>

Co-authored-by: Ahmad Abdolsaheb <ahmad.abdolsaheb@gmail.com>

curriculum/challenges/english/11-machine-learning-with-python/machine-learning-with-python-projects/book-recommendation-engine-using-knn.english.md

@@ -2,7 +2,6 @@
 id: 5e46f8e3ac417301a38fb92f
 title: Book Recommendation Engine using KNN
 challengeType: 10
-isHidden: false
 isRequired: true
 ---
 

curriculum/challenges/english/11-machine-learning-with-python/machine-learning-with-python-projects/cat-and-dog-image-classifier.english.md

@@ -2,7 +2,6 @@
 id: 5e46f8dcac417301a38fb92e
 title: Cat and Dog Image Classifier
 challengeType: 10
-isHidden: false
 isRequired: true
 ---
 

curriculum/challenges/english/11-machine-learning-with-python/machine-learning-with-python-projects/linear-regression-health-costs-calculator.english.md

@@ -2,7 +2,6 @@
 id: 5e46f8edac417301a38fb930
 title: Linear Regression Health Costs Calculator
 challengeType: 10
-isHidden: false
 isRequired: true
 ---
 

curriculum/challenges/english/11-machine-learning-with-python/machine-learning-with-python-projects/neural-network-sms-text-classifier.english.md

@@ -2,7 +2,6 @@
 id: 5e46f8edac417301a38fb931
 title: Neural Network SMS Text Classifier
 challengeType: 10
-isHidden: false
 isRequired: true
 ---
 

curriculum/challenges/english/11-machine-learning-with-python/machine-learning-with-python-projects/rock-paper-scissors.english.md

@@ -2,7 +2,6 @@
 id: 5e46f8d6ac417301a38fb92d
 title: Rock Paper Scissors
 challengeType: 10
-isHidden: false
 isRequired: true
 ---