Added Problem 1143. Longest Common Subsequence in JAVA

Description

Added multiple approaches to the LeetCode problem 1143. Longest Common Subsequence (memoization -> tabulation -> space optimization) in JAVA.

Put check marks:

Have you made changes in README file ?

• [✓] Added problem & solution under correct topic.
• [✓] Specified Space & Time complexity.
• [✓] Specified difficulty level, tag & Note(if any).

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Please also note any relevant details for your test configuration.

• [✓] All testcases on LeetCode

Make sure all below guidelines are followed else PR will get Reject:

• [✓] My code follows the style guidelines of this project
• [✓] I have performed a self-review of my own code
• [✓] I have commented my code so that it is easy to understand
• [✓] I have made corresponding changes to the documentation
• [✓] My changes generate no new warnings
• [✓] Any dependent changes have been merged and published in downstream modules

I can tell this is your first pull request! Thank you I'm so honored. :tada::tada::tada: I'll take a look at it ASAP!